The only Fort Jackson I know of is an active army base in Columbia, and definitely not a tourist stop. Now Fort Sumter is one of many things to do in Charleston SC, along with Patriots Point with a WWII aircraft carrier, planes, a submarine, and a destroyer. You can do a lot of walking in Charleston through the old market, along the waterfront, and get some really good local cuisine. I think the place you want to try to get into is John Island County Park. (If I got the name right). A very nice place to stay and even has a shuttle to downtown Charleston.
Columbia doesn’t have a wealth of campgrounds, and quite frankly other than the State Museum and Confedreate Relic room, not sure what there really is to do, unless you can catch a USC football game ... There is a nice state park near Fort Jackson (fairly central) called Sesquicentennial Sate Park. Good place to stay for a night anyway. There are also two state parks on lakes but they are both 20-25 miles from Columbia in opposite directions. One it Lake Wateree State Park which I really like, the other is Dreher Island State Park on Lake Murray.
I second the Tybee Island, and there is a Fort near there, just don’t think it’s Jackson. I suppose there could be two of them....
