This is one of the best dispersed camping areas around Moab.  The location is north of Moab by 25 minutes or so.  Right on two mountain bike trails - Sovereign Single track (great for intermediate and advanced riders) and the Klonzo trial system (great for beginners).

There are great moto options all around too.  The road can be a little rough getting back to these sites so lower clearance vehicles may have some trouble.

Great location, great riding, and free.