Dead Ringer is a fun singletrack in the JEM riding area. It extends from the upper (Highway 59) JEM trailhead downhill to end on Cryptobionic just north of Sheep Bridge Road.
The Dino Cliffs Trail is a singletrack route along the low red cliffs just north of Washington. The trail itself is short (1.8 miles), but you must ride dirt road to get there. The ride is 4.3 miles as a loop and about the same as an out-and-back.