I say the same thing about Louisiana...
Georgia is going to be your best bet. The wife and I go there pretty much every year and the best we have found is to stay in state parks and explore the surrounding area. We stay at Vogel a lot because there are a lot of hikes around there and a lot of waterfalls, which the wife really enjoys. We found a couple "trails" to drive...one in particular outside of Dahlonega, but it was very tight and my lifted Tundra barely made it thru and there were a few downed trees that I barely fit under. The trail was too narrow to turn around, so if I didn't make it under the downed tree, I would have had to back down nearly 7 miles of twisty curvy forest road. Not very enjoyable. Plus there was nothing to see...just a narrow dirt road thru a forest.
Pretty much everything east of the Rockies is private land, so the only option is to hit state parks and hope for the best. A couple state parks in Arkansas has designated trails and ATV areas and we just got back from 10 days in Missouri where the only off-road I saw was St Joe State Park that had a huge area for ATVs.
If you want to camp away from people like we do, we go to Georgia, Arkansas, North Carolina in the off-season and stay in camp grounds that are relatively empty at that time and then go hit the empty trails that are normally crowded in the tourist season. We did a week at Cloudland (just south of Chatanooga) in January and it was in the 20-30s temperature wise, but we had the entire campground to ourselves. It was actually very nice...hiked without sweating or seeing people.
