There's an outfit called Oconee Outfitters that has sponsored road races in the past. Give them a call.

http://www.oconeeoutfitters.com/

I used to live in Athens, about 30 minutes or so north. There's no shortage of country roads although the drivers aren't trained very well. If you did drive up to Athens there are some organized rides you could join. The Hub has a list on their website.

http://hubbikes.com/page.cfm?pageID=47

Also, you'll be in the Piedmont, so nothing totally flat but some decent rolling hills.