Lots of rocks, dust if it's dry, mud if it's wet. There are no steep hills or trees, and the trail is pretty wide. The MX track is way cool--one of my favorites--and the trails are a combination of old, burned in trails that you can rail because they're worn down like a ditch and new ones with off camber rough corners. The crappiest part of the whole thing is the part where you have to PUSH your bike across the road (there's a checkpoint there so no fudging) but it's not too bad. It's a pretty high speed, hang onto the bars course. They usually run it about 7 miles long and they give you a parade lap so you know where you're going (though I've never gotten lost--it's fairly well marked). I always go back and forth about taking the parade lap--in one respect, then you know where you're going, but on the other hand, you waste precious energy. I wouldn't recommend iron-manning it unless you've done it before.