system in the US. Go for all the black diamond stuff. You can ride around on the fire roads, but in my opinion, that is pretty boring. Get a good map of the Paiute trail and look for the more challenging stuff.

There is one trail in particular below Cedar Mountain when you come down into Richfield that goes through a ravine. I think it's trail 66, but I can't remember for sure. The top of the trail is marked as double diamond or "most challenging" or something like that. The ravine is only a couple hundred yards long, but its filled with boulders the size of small cars, and you have to take your time navigating down the trail and need to make sure your ATV has the right equipment, but it's a lot of fun.