Farmingdale is a blast, especially for a sport quad or dirt bike. It has alot of badlands type hills with jumps and hillclimb areas. Also has a few "racetrack" sort of areas, all natural terrain. I've only been out there once, and definately didn't explore the whole area. Lots of ground to cover.
I don't think you need a permit, you don't if you are a resident, so I would assume a non-resident wouldn't need one either, but I wouldn't just take my word for it. I know that you can't drive on public roads without a plate though.