Do not try to ride Gnargasm when wet. The the is exposed and it is slippery when wet. These trails are known by county officials but are unofficially supported and maintained by the Austin Ridge Riders through the Brushy Creek Builders, aka BCB.
If you start at Olsen Meadows Park, head west on the Brushy Creek Regional Trail until it heads into the woods. Right before it heads into the woods, you'll see a trail that heads South. That is the beginning of Gumdrop. This trail travels along the South side of the creek. It is fairly flat with not very many technical features. It will eventually lead you to Snow White. Snow White heads up the ridge South of the main trail. There are a few mild climbs and descents on the trail. The entrance to Gnargasm is on the West side of Snow White. Gnargasm is a one way trail starting there. It is a exposed climb up the ridge. Eventually you come to a spot where you ride out on to a large boulder and then ride a berm back down to safety.