Anybody ever get out to some of the state forest lands in Northeast PA? Delaware State Forest is 80,000 acres and only about two hours from most places in Northern NJ. Lackawanna, a little further west is 27,000 acres. Maybe not a day trip, but probably a good place to camp and wheel-they have great maps online too:
Most PA State Forest allow ATVs, so they definitely don't have a problem with trail riding.