A combination of smooth dirt road and rugged 4WD track that is actually pretty fun to ride down. From the end of the pavement on Flagstaff Road (Lake Shore Drive at that point) ride northwest on a smooth dirt road.
You'll pass through a cluster of houses that may make you feel like you're trespassing, but you're not. This is a public right of way. The going gets steeper and rougher as you make the big left turn, but generally isn't very difficult. You'll eventually top out onto the ridge and begin a gentle descent. The road is really washed out in parts, adding to the excitement. Right near the end of the trail, it will get a lot steeper and more blown out.