From the trail head, the trail starts on single track through the woods, and frequently borders the lake. This single track session lasts for about 5 miles, and criss-crosses a horse trail. The horse trails are not open to bikes, and are clearly marked, so there should be no problem there.
After about four miles, right after a bridge spanning Park Creek, you will come to a cross roads. If you go right, you will come to a nice waterfall, and pool. This is a good place to take a cool dip on hot days, the pool is MUCH cooler than the lake! If you go straight at the cross roads, you will find a half mile fire road climb, rewarded by a fast fire road downhill with a couple of fun jumps. If a left is taken at the cross roads, you will take a rolling single track trail, which meets up with the fire road after about a mile.
Once trails meet up, you enter into the main park area, at the Hazel Creek campground. At this point, the trail goes in and out of the various campgrounds, and is in part single track, double track, and occasionally on the paved road. Keep an eye open for trail signs, as you go in and out of these sections. They are all marked, but it is easy to miss a turn, and have to retrace your route a little bit.
I usually camp here several times a year, and stay at the Hazel Creek campground. This allows me to start at the single track, and ride the trail backwards, and make it an out-and-back, with single track the whole way, instead of a loop.