There is some decent singletrack if you venture off the main trails.  You will have to cross the creek a few times (once on the trail) in order to get to the majority of the good singletrack.

Once you see the Onion Creek play ground the start of the trail is towards the creek, about halfway in between the playground and the creek

Noteworthy:
 -Horses use this trail a lot... keep your eyes peeled for their remnants
 -There are some rocky areas on the trails
 -Nothing is marked
 -If you are experience and looking for a techincal ride, this is not the trail for you