This is a 4x4 trail that is a load of fun. It is not that steep but there are lots of bike steps that you have to climb (and get to descend!). The view at the top is unbelievable. Not classic freeride or XC but definitely worth your time if you are a true MTB fan!
From Moab take Hwy 128 North to Dewey Bridge or from I-70 take hwy 128 south to Dewey Bridge. There is a camping area at the bridge, the trail starts at the bridge.
http://www.singletracks.com/item.php?c=1&i=2082