There is a lot of dirt road in the National forest land by the Ocmulgee river south of Jackson Lake. I used to go there from Covington GA a few times a year before I knew about ORV parks. Look on google maps etc.... THis is east and south of Atlanta. Its just forest service roads but its legal. Take highway 16 from Griffin / Jackson and enter in a Concord church road. You can make your way south to Juliette, hug the river. There is even a great redneck swimming hole in there. Then come back up on the highway to Indian Springs its a nice drive.