Definitely do the Silver Comet while you are here. The beginning sections are pretty congested with pedestrians, but still nice rides if you don't mind being polite and braking a lot. Otherwise it is just frustrating. Out about the Seaboard Dr access it really opens up. The section beyond the Rambo(Rambo Nursery) access is delightful with high trestles and a tunnel. The rest is rural except for the Rockmart and Cedartown areas.
If you are up for back to back centuries a weekend round trip is fun. There is motel in Jacksonville near the AL end.