I guided the Chattooga from '99-'04 so some of my local knowledge may have changed. Depending on what section(s) you plan on running there are a couple of logistical things to consider. Any access from the SC side of the river will require a minimum 1/4 mile hike with all of your gear from the parking lot to the river. There was access to Sandy's Ford and Earl's Ford that did not require the hike to the river. If you plan on rafting Section IV there is a 2 mile flat water paddle out to the boat ramp on Lake Tugaloo.
Camping in the area, when I was there, existed at Woodall Shoals, Earl's Ford, and Sandy's Ford on the SC side. The town of Long Creek, SC has grown up quite a bit in the past 10 years and would be a great place to talk to the locals and maybe get some better ideas for free camping in the area. Chattooga Whitewater Shop would be my first stop. It will is pretty much impossible to miss bringing 441 N to Clayton and then 76 E out of Clayton into Long Creek.
Also, if you're not already aware of it, there is a more SE specific forum boatertalk.com that may be a great place to network and develop some paddling buddies while you are hanging out in HotLanta.
Feel free to PM me if you have any further questions or questions about the river in general.