There's a couple of local 4wheeling clubs in the area. Most 4 wheel excursions go out of the area to legal pay-to-play areas. Some members have private land that they sometimes take people on, but those are usually by invite only. Don't ask to be invited.
Maryland Creepers - Powered by vBulletin is a good place to start.
ParagonAP.com ATVs & Motorbikes is a good place to wheel.
As far as Buck Hewitt Road, it's all private land. I have "rescued" a few jeeps and other trucks outta there for co-workers. The risk is there.
I just purchased a new jeep and I'm brand spanking new to wheeling. Any updates regarding locations to off-road in southern MD? Looks like that paragon place is closed.
Thanks!