GWNF is definitely the only place close by. Used to be able to go to Paragon up in PA but that's been closed (I think they are building an airport or something up in its' place).
There are also places near the whole VA, KY, TN border but as far as someplace close,.. definitely GWF.
Once you get to Harrisonburg, VA... go west on 33 through town... you're go around 8--10 miles or so.
Keep your eyes open at like 9 miles for McDorman's Grocery on the left. Stop here for last gas,.. and Country Ham Sandwiches... mmm, mm.
Once you are there,.. about another 2 miles or so you'll start seeing openings in the trees to the left... these are trails. there's a few to the tight also,.. also trails,.. and more rocky than mud...
Definitely get the Gazetteer or a modern GPS with topo maps built in. Look for 2nd Mountain...
There's primitive camping available everywhere there... you'll see where people had fires all over the place (kind of against the whole leave nothing behind mentality).
There are usually peiple out there 7 days a week,.. depending on school/work schedules.
Brandywine campground is nice too for actual spots with power... it's in WV just a few miles up 33.
You'll actually be in a national forest but there are no fees to go out to these state maintained areas.
There are also places to go off-roading further north off of 81. Do a search for Woodstock Tower area.. there are ATV trails of varying difficulty all over that area... I've taken my 4Runner there.. would hesitate taking the Landcruiser as some of the trails get narrow.. most are nice and wide though.
In this area though... you have to pay a fee and get a daily ticket... 90% chance you won't get caught.. but I like to plan for that 10% where I will so,.. get the ticket. It pays for trail maintenance... an keeps the place open for us to use.
Have a great time... and if anyone here wants to head up there.. I'm looking for people to go up there with... sadly I have a cookout at the house this Sunday

.
v/r
Bill
PS: If you have a GPS...:
Jeep Horizons :: View topic - GWNF Dry Run GPS Coordinates?
GWNF - FJ BRUISERS SPRING mudFLING (5/4 - 5/6) - Toyota FJ Cruiser Forum
There are some coordinates and pics of what to expect.