The Emma McCrary Trail is a nice singletrack that was built by many volunteers and spearheaded by the Mountain Bikers of Santa Cruz. It is a beginner friendly trail (no more than 7% grade, but usually much less than that) that runs from the trailhead at the end of Golf Course Drive to the intersection of the U-con Trail
and Rincon Trail.
Descending, Emma McCrary Trail is particularly yummy, as it is rolling with many nicely bermed sections. This trail runs through lush groves of redwood trees.