From Atlanta for a 2 hour(ish) trip lets see....
1. Beasley Knob (N.E. GA) closed Jan 1st - Mar 31st and closed after heavy rains
2. Durahmtown (E. GA) private park
3. Various forest roads above Helen but I really have not seen a road that is worth driving for the 4x4 part. Ok for day trips, hikes, picnics, but no road has been good enough to be the focus of a trip.
4. Morris Mountain (AL) private park open 2 weekends a month
5. Choccolocco Mtn (AL) private park
6. Great American off road park (Auburn, AL) private park, mostly mud from what I hear
7. Aetna (TN) not a real park, strange public/private land thing but is legal for now
8. Coal Creek (TN) private park, could be pushing the 2 hour mark for some
9. Gulches (SC) private park
There might be more but you get the idea. GA is a HORRIBLE state for off road vehicles. Most of the "spots" here are illegal and with the mind set that people have been going to whatever illegal place for years so its ok. To do it it legal in this great state you need a rig that can handle the 2+ hour drive or a tow pig, and the money to pay the fee to the parks.