Here are a few places to ride that are conveniently located to Kadena AB.  I hope to expand this page to include other areas. Send me a description of your favorite trail and I'll post it here.

Barking Dog (Kadena) 

Overview 
 Barking Dog (named for the military dog training area it passes by) combines fence-line singletrack and farm road riding over undulating terrain.  There are no major climbs, but there are a few short pitches that can be quite challenging.  This makes a good warmup for Spider Loop (see below) and also makes for an excellent after-work ride for midweek tune-ups.

How to get there (5 min., 4.5 km)
Turn left onto Route 74 out of Kadena AB Gate 3.  Follow Rte. 74 (this road usually has several farm stands and ice cream trucks parked along it.) for 3.5 km to the first traffic light.  There will be a sign that points to the right that says "Kadena Athletic Park".  Turn right and follow the road .8 km to the end.  The dirt road to the right is the start of the trail; the parking lot is to the left.

The Trail
Follow the dirt road out of the parking lot; in fairly short order it will parallel the chain-link fence that will be your guide for the initial section of this ride. Once you reach the fence, look behind you for a large green water tower and a couple red-and-white-banded smokestacks; these landmarks are your friends and will guide you when you get lost further up the trail. When the road takes a hard left and the fence bears gently right, follow the fence. This section is more likely to be watch-out-for-habu tall grass than it is to be putting-green-smooth. You pass by the military dog training area (and dog cemetery), and several interesting Okinawan tombs.

As you climb away from the tombs, you encounter an intersection with a farm road coming from the left and then veering away from the fence again. Follow this road away from the fence (the remaining fence line trail makes for an interesting diversion, but I don't consider it worth the effort). You'll know you're on the right track when the dirt road turns nearly straight up; don't worry, it's rideable - really.

You're now facing a network of farm roads with many opportunities for getting lost and/or riding in circles. If you look back to the south you'll see the water tower and smokestacks. To the northwest you'll see some high-tension power lines and an apartment building with "Mansion Route 58" on it. Your general direction is north, parallel to Route 58, and toward the "Mansion".

After ~1 km you will cross a paved road which leads to a gate into the Munitions Area. You'll see Rte. 58 100m to your left and a power line tower immediately in front of you. The dirt road becomes gravel and is somewhat wider, with a slight downhill grade. This is a great section to bomb through, just watch for traffic - pedestrian and motorized.

There's a spring where the downhill bottoms out; keep left. Go about 40m past the spring, downshift, and turn hard to the left up "Tomb Hill". When you reach a T-intersection, go right, then take your first right. You're still heading north. At the next road go left, then right. After maybe 700m the road forks to the left; this turn is easy to miss because the fork is more like a trail than a road (yeah!) - it plunges down into sometimes-dense vegetation and the surface is anything from rocks to deeply-rutted mud, all in the space of 100m or so.

Assuming that you found the fork, just follow the trail until you pick up the fence line again. Don't forget to close your mouth or at least grit your teeth when you climb past the beehives (usually only a problem during the warmer months). I nearly inhaled a bee once and it was No Fun. Turn left when you see the fence, and follow the dirt road until the fence takes a 90-degree bend to the right. Follow the fence. There's a fun little drop off at the bottom of the hill. Continue along the fence until you come to a paved road. More often than not you'll see one or two cars with bike racks parked here. You have now arrived at the start of Spider Loop.

Spider Loop (Yomitan/Ishikawa) 

Overview
Spider Loop (for want of a better name - also known as "the same old place we always ride", or simply "The Fence")  is a favorite place for advanced mountain bikers to hone their technical skills; in fact some will tell you there's no place else on Okinawa to ride.  It consists of a series of short trails, each with its own character.  The Loop is mostly singletrack, with surfaces ranging from dirt to clay to gravel to (ugh) pavement.  There are gnarly technical climbs and bugs-to-fill-in-the-gaps-in-your-smiling-teeth downhill plunges. If you ride at all aggressively, then suspension is a must.

How to get there (10-15 min., 8 km)
Turn right (north) onto Route 58 out of Kadena AB Gate 4.  Follow Rte. 58 approximately 7 km north until you see a restaurant on the left with 3 large pigs and a steer out front.  You can't miss this.  Go .9 km past the pigs and there will be a traffic light.  Turn right and go to the end of the road. Park here.

Fence Line to HLZ 

Overview 
 This section is the start/finish stretch for most rides on Spider Loop. It follows the fence line around the Munitions Area to the base of the HLZ trail, with options to branch off to Double Drop (and thence to Paintball) or to the Mother of All Downhills (which becomes Uphill in this direction - definitely not recommended, and in fact, discouraged). The trail is wide and easy to negotiate, although heavily eroded in places.

The Trail 
The trail is on the left side of the road as you face the fence. (Going to the right sends you back down Barking Dog). A short (100m) hill will raise your heart rate in a hurry. From this point on you will be following a flat red clay road strewn with rocks and eroded down the middle. Just follow the fence until you come to a hard right bend and a sign to the left that says "HLZ 1/2 mile". (Some folks like to continue along the fence until they reach the top of Blurred Vision.)

HLZ 

Overview 
The entrance to HLZ marks the beginning of the 1+ km climb to the Hawk missile site.  This trail is also used by motorcycles, so beware! The surface is almost entirely  red clay which gets very slick and sticky after a rain.  The stuff clings tenaciously to your bike and is almost impossible to wash out of your clothes.  The trail is fairly wide singletrack, but it's heavily eroded and therefore makes choosing the right line an exercise in careful planning.

The Trail 
At the first sharp right-hand bend in the fence line trail there is a sign nailed to a tree that says "HLZ 1/2 mile". (I tend to think this is 1/2 km...)   Just follow the trail to the clearing at the top.

Spider Alley 

Overview 
This tree-covered dirt singletrack gets its name from the banana spiders that like to build their webs across the trail. The spiders are harmless, but they're HUGE and so are their webs. Yuck. Let your friends go in front.

The Trail 
From the top of HLZ, cross the clearing (about 100m) until you come to an opening in the brush.  About 30m up the trail you will see a sign nailed to a tree high up on the left that says "Spider Alley" (and a bunch of other stuff).  Follow this trail until you reach a paved road.  If you failed to climb the last sharp uphill pitch on HLZ then you have a chance to redeem yourself at the end of Spider Alley; this one's longer and harder, though.

Blurred Vision 

Overview 
This downhill is over too soon for those who are brave/foolhardy enough to attack it head-on.  It's a nearly-straight shot with a couple slight turns thrown in to keep you honest. There's a fence about 6 inches off your right bar-end and a nasty crash zone about 2 feet to the left. Down the middle is a well-trodden and eroded 6-inch-or-so swath that alternates between irregular stair-steps and concave pits that look like foot-long divots.  It's a rough ride that will leave you feeling like you've been ballin' the jack when you're through.  Blasting down this thing on a full-suspension bike is a rush that I've only been told about and have yet to experience; I have a family, after all.

The Trail 
From the top of Spider Alley, cross the paved road; there's a sign to the left that points up the hill to the Japanese Hawk missile site.   This is a good place to rest and regroup; there's a great view down to the Pacific side of the island, from Okinawa City up through Ishikawa to Kin.

Once you're ready to start out,  ride in the drainage ditch until you can get back up close to the fence; about 20m.  Let the mad bombers in your group go ahead of you (I usually go near last unless I've had a lot of coffee that day).  Look at the trail in front of you as you go down (not at the 4-foot drop-off into the deeply eroded red clay and rocks on the left, nor at the chain-link fence 6 inches away from your right handlebar that would just love to grab your bar-end and throw you into the afore-mentioned erosion gully) since bikes have this tendency to go wherever your attention is focused.  Near the bottom there's a bend to the left, still along the fence. Immediately after you cross the drainage ditch at the bottom, crank your bars around to the left to climb away from the fence.  Once you start back downhill again, look to the left and you will see a sign nailed to a tree that says "Waterfight".  There's a gate in the fence to the right, and the trail ahead is definitely doubletrack.  Back and to the left is some overgrown singletrack that was probably cut by the bird collectors you sometimes see in the area; it goes back in along a ridge for a fair distance but dead-ends.

Waterfight 

Overview 
It's your choice: you can either use this section to recuperate from the the punishment you've endured so far, or you can blast on through and just get tired.  If this were a race course then you'd be desperately trying to pass people here.  It's all wide "doubletrack" that continues to follow the fence around the Munitions Area, although the erosion ruts tend to limit the choice of lines down the trail.  In general, keep left.  After a rain this section will really gunk up your bike unless you ride slowly and carefully - but that's not much fun, now is it?

The Trail 
It starts out as a relaxing double-dip roller coaster ride that follows a wide trail along the fence line. The surface is mostly loose gravel, with small-but-treacherous erosion gullies down the middle of the trail. In general it's best to keep to the left, even if that means you'll pick up a little more mud.

And speaking of mud, the bottom of the second dip is almost always a wide swath of the gooey stuff, with a sharp uphill right turn on the opposite side. This is another place to let your friends go first, so you can gauge how they handle the conditions.  After this it's a fairly flat, sometimes undulating run until you come to a reverse fork on the left (Buddy Junction).  If you get to a dead-end gate, turn around and look for a right uphill fork about 400m back the way you came.

Buddy Junction 

Overview
This is the last climb of note on Spider Loop (unless you're doing The Mother - then you have to climb back up to that). It's short, but it's still nasty due to all the crap you've had to endure in order to reach this point.

The Trail
There's only one way to go and that's up.  The initial pitch take you to a clearing on the right. The surface is more of that wonderful red clay, but there's usually enough debris from the overhanging vegetation to provide something for your tires to dig into if the clay's too slick. Past the clearing the trail briefly turns down and to the right, and there's usually mud at the bottom. Next comes a hard left uphill turn and more grunting and grinding, past a small field of bird-of-paradise flowers and ultimately to a paved road.

 Stairway To Heaven 

Overview
What's to say? It's like a commercial break thrust into your favorite TV show. It's nothing but road riding and walking. Ick. But don't worry, it doesn't last long, and the road ride is actually a good recovery section.

The Trail
At the top of Buddy Junction, turn left on the paved road. Follow the road past a hotel and golf course on the right until you reach a picnic area on the left. This is an excellent place to refill your Camelbak and/or water bottles. Pick up your bike and walk up the 212 stairs to the observation tower. I don't know anybody who enjoys this part. The 360-degree view from the top makes it worthwhile every time, though.

If you don't feel like climbing the stairs then you can wimp out and take the bypass.
 

La Luge 

Overview
This is the Reason For The Ride. It's a twisty, technical downhill plunge through the jungle that might just make you want to do the climb all over again. Watch out for hikers if you're alone or the first in your group, especially near the end of the trail where there are several interesting tombs and caves.  The top section is quite difficult for most of us mortals; very narrow with lots of roots, drop-offs, and few (if any) clear lines. You can get through it reasonably well if you're willing to sacrifice your upper body a bit (ok, you have to ride it at least once to understand...) and lay off the front brake. The rest of the trail alternates between very narrow convex and very narrow concave in cross-section; one minute you'll be in a half-pipe with walls over your head and the next you'll be looking at a 50-foot dropoff on either side of you.  It's always a rush.

The Trail
From the observation tower there's a trail that heads sharply down the back (southwest) side of the hill (facing the Hawk missile site and Yomitan). At the bottom of this section (about 30m) the trail turns sharply back and to the right.
Don't miss this turn! It could hurt...alot. There's a sign at this point that says "La Luge - Watch For Hikers!".  The remainder of the trail is singletrack all the way to the bottom, with no obvious way to get lost. You'll know you're near the end of the trail when you emerge from a small bamboo thicket and get hit in the face with a spectacular view down the west side of the island. Don't stare longer than a half-second or you'll be off the trail. About 100m past this point you'll plunge back into the jungle and the surface becomes extremely rough. Don't crash here - it's all coral & limestone. A hard left turn at the bottom of this section carries you out of the jungle, where there's a house and a few signs, all in Japanese of course.

From the house you have several choices as to where to go.  Here's just one way:

Follow the trail behind the house until you come to some stone steps, about 50m. Carry your bike up the steps,.then follow the trail straight ahead and around a sharp right turn, down to the road. (Just past the top of the steps is another set of stone steps that lead down to the right of the trail. Hardcore folks ride down these steps and continue down the short steep trail to the paved road. I don't recommend doing this without somebody to watch for traffic at the bottom. In fact, I'm too wimpy to try it at all, but many others have, and survived, and had fun on all accounts...) Turn left on the paved road and climb until you reach a T-intersection, about 200m.

If you turn right at this point then you'll wind up on Route 58 in very short order. You can follow this all the way back to the parking area if you like.  There are a couple interesting diversions along the way, but the best way to find these is to have somebody show you where they are, or to discover them for yourself.

If you turn left at the T-intersection then you'll continue on the paved road past some gravel piles and a concrete mixing plant, around a sharp left bend and up a reasonably steep hill.  When you reach some high-tension power lines there will be a dirt road leading off to the right - it deceives you at first with a short, relieving downhill, but quickly turns into a mean little uphill grind on loose terrain. (If you follow the paved road around a left-hand bend and beyond the power lines then you're either going too far or perhaps just finding your own way). Follow this until there's a trail to the right, about 300m (if you're measuring this then bear in mind that this one's a big "guesstimate"). Take that right turn uphill and there's another right turn that leads down hill for a very long way. That's The Mother.
 

La Luge Bypass

Overview
If you've at least tried the top section of La Luge more than once and decide that's it's  just not your bag (or maybe you just don't want to climb those stairs, you girly-man you), then you can take the way around the nasty stuff that still lets you enjoy the ride on the bottom part.

The Trail
Instead of climbing the stairs to the observation tower, look for a dirt road to the left where the paved road turns sharply to the right, just beyond the picnic area. Follow this road until you see a trail to the left, about 200m. (The road continues on for a fair distance beyond the turn, paralleling Rte. 58). The trail takes a short downhill dip, then climbs up to the right, twisting a couple times until you reach a clearing around the base of a high-tension electric tower.

Cross the clearing and look for an opening in the brush to the left. The trail is very narrow and twists sharply, affording many opportunities to become closely acquainted with the vegetation. The end of this short section opens onto La Luge, just beyond most of the root-infested endo-inducing stuff.
 

The Mother of All Downhills 

This one rivals La Luge and Blurred Vision for the Adrenalin Rush award. What makes it even more interesting is the rope gym (no kidding!) that a certain Mr. Bill Finch has constructed over the stream at the bottom. Even if you're too cashed at this point to play on the ropes, you have to admire the man's dedication to his art (incidentally, Bill is also a master of the Art of Trail Maintenance and Construction-- all bow and give thanks to The Bill). And speaking of art, there's a sculpture-in-perpetual-progress hanging from a tree in the same vicinity. It consists mainly of trashed bike parts, artfully arranged. Feel free to add yours; if you don't have any bike parts that are sufficiently damaged when you start out, you may have some by the time you reach the end of The Mother.

The Trail

Somebody else is going to have to write this one up... I don't ride it enough to do it from memory.  Sorry!  If you've gotten this far looking for guidance, the best I can do is refer you to OMBA.
  

Paintball (Yomitan) 

Overview
Technical!  Need I say more?  Ok, I will...

This is a short (about 5k) loop that follows the fence line around an area that's used for paintball games and little, if anything else. There are no major climbs but a couple short, steep pitches. It's almost entirely narrow singletrack, with the rusty chain-link fence on one side and drop-offs of varying heights into the woods on the other side.  The surface is primarily clay and rock, with debris from the overhanging vegetation and a few randomly-placed spider webs thrown in, depending on the season. Most of the trail is narrow and punishing, with very few choices of lines: either you get it right or you get hurt, or at least embarassed.

How to get there
Follow the same directions as you would to find Spider Loop.  Instead of turning right at the last traffic light, turn left. Park here.

The Trail
Simply follow the fence, keeping it on your left.  Once you have passed the initial climb (about 1km) exercise extreme caution if this is your first time through and/or you have no guide! Paintball has many surprises. Also, try not to lean too far to the right - ride a nice clean line if you can. Otherwise you may be buying a new helmet sooner than you had expected.