The tourist areas of all three cities are quite small and very walkable. Savannah about 1 square mile back from River Street, Charleston a bit bigger but it has a good tourist bus system, Atlanta downtown small but the suburbs are huge. A strategy of find the closest Holiday Inn Express that has free parking would work for all, though stay off the roads at rush hour, or pay the higher price and stay right in the middle of the tourist areas. Driving on the interstates between the cities is very boring but there are some very nice attractions just off the interstates if you want them. Any state park, and there are a lot of them, will be a nice spot for a few hours. There are also good beaches on the coast and good Civil War attractions near Atlanta. Kennesaw Mountain is one of my favorites.