Enter park and proceed west to gate. Trailhead is due north of gate. This a very fun set of trails, single track with lots of curves, tons of ruts, and a couple of good drops. Not a difficult set of trails, but you must have some skills to ride this one. Look for jumps halfway through trails, they are worth stopping for.
Upper lake offers paved riding for wussies.
Trail located behind Murry park which is just north of lake Hefner on Hefner Rd. I am a sport level rider and I can complete the trail in a little over 20 minutes. It is mainly a trail for locals who don't want to drive to better areas. However, there are many fun parts to the trail and mastering the tight corners does take some practice. If you are close to the lake Hefner area, I would recommend it, otherwise, it is not worth the trip.