First, welcome aboard.
You're new so probably not wise to the "rules" of talking openly about locations (other than known public OHVs or parks) on the web, short version is that it's usually a bad idea.
If you search through the threads you'll find a few spots or hints of spots but there's absolutely nothing LEGAL near ATL, you'll have to go to Beasley, Durhamtown (See Pig Roast in 2 weeks) or shoot to Alabama for the closest wheeling. Of course, there's always Forest roads in north Georgia if that's your thing.
Frankly, the best way to find wheeling locations is to get into a group and you'll learn from there. FYI--Meetings are first Tuesday of every month.
Now go forward and Tread Lightly!