Ga 60 between US 19 and US 76, Ft. Smith to Morganton Two Wheels Only campground used to be right where Ga 180 tees into 60 at Suches. 180 is also called Wolf Pen Gap Rd., and is definitely a must ride. In fact, if you started in Ft Smith and headed North up 60, ran 180 over to US 129 and back, continued to Morganton and then just backtracked to Ft Smith, that would be a fantastic ride. US 129 between Ft Smith and the East end of 180 is also good, but there can be traffic and it is usually patrolled.
http://www.twowheelsonly.com/
If you will be riding a dualsport, there is NO END to the great riding!!
So anyway... back to the street thing...
Look in the upper NW corner for a town called Chatsworth and East Ellijay. There are three good roads that run basically East West between US 411 and Ga 5. Ga 2/52 is also called Chatsworth Highway and connects the two towns. To the South is Ga 282 is also called Tails Creek Rd. Last is Ga 348.
If you want more fun, head up US 76 from East Ellijay to Blue Ridge and go North on Ga 5 to the Tennessee border. It becomes Tn 68. Run that all the way up to Tellico Plains. It is a fantastic ride, especially if you are there on a weekday. There is camping in this area. You can then run East across the Cherohala Skyway to Robbinsville, NC., and then up US 129 to Deal's Gap (can camp there was well). From here, I would run down NC 28 all the way back down into South Carolina. 28 is another fantastic ride. Just inside the SC border, look for Pine Mountain and head West on Warwoman Rd., and start working your way back to the North Atlanta area.
You could spend weeks in that whole area and barely scratch the surface of some absolutely incredible riding... even if you just stick to the pavement