I don't know of any that offer both camping and rafting/camping. Toad is right about Helen - there is the Chattahoochee River there with lots of both. Closest CG that I know is back toward Cleveland, Yonah Mountain CG. Maybe drive your towed and park it at the take-out area (lots of parking) and ride the bus back to the starting point?
horsedoc
2008 Damon Essence
2013 Jeep Sahara Unlimited
Blue Ox tow