Park at the first small parking area on your right upon entering Nepco Lake County Park. The trail starts across the road to your left and is a one-way trail. You'll turn right and follow the brown arrow signs. It might take a few laps to get acquainted with the trail, since it's not extremely well-marked, but your patience will be rewarded! There are lots of twists and turns, some terrain down by the lake, and quite a bit of sand.
It's easy to get turned around, so I'd recommend studying this map before heading out and using the MTB Project mobile app
while out on the trail. This trail is 100% free all the time and open year round. Drainage is great, since there is a lot of sand.