This is a pretty good trail system with lots of options. The trails north of the lake seem to have less sand and more singletrack including a pretty good DH off Terri Peak.
You can also connect with other trails outside the park for longer loops.
The Lake loop is best clockwise.
There are numerous access points to the trails throughout the park.
http://www.singletracks.com/item.php?c=1&i=8000