If it were me, I would prefer to get south of Atlanta the first night. Otherwise, you will either have to plan to get through Atlanta before 7 AM, or either be in the rush hour or be late enough to miss the rush (and then get to Disney way after dark). South of Atlanta, there are two state parks not far off the I-75, High Falls in Jackson and and Indian Springs in Flovilla. Also in Jackson is Forest Glen Estates RV Park. As already mentioned, there is a KOA in Forsyth. In Macon, is Lake Tobesofkee Park. Further south is Insterstate RV Park in Byron. Going further south there are many, many campgrounds.
