You're limited. The GWNF is not geared toward off roading. Over in the Harrisonburg area they have closed many trails due to them being in the water shed area for the city. Hook up with a Jeep owners group, NovaJeepers, SouthSideJeeps, or someone. There are some trails down around Crabtree Falls but thats a little ways from you. There is a privately owned off roading area and club in Crozet, outside Charlottesville but its for rock crawlers. Then there is BigDogs in Gore Va.
American by birth, Southern by the grace of God.