V.W.
Depending upon how far off of I-95 you are willing to go, there are several points of interest you might consider around the Savannah area and also on Jekyll Island.
There is an Air Force Museum just off I-95 at Savannah, GA.
http://mightyeighth.org/
At Jekyll Island there is a historic district that has tours of the millionaire's village. And if you want, you can even stay at the Jekyll Island Club Hotel (the original millionaire's club retreat)... There is more history on the island than JUST the historic millionaire village, but that is where you can tour the homes.
http://www.jekyllisland.com/About/HistoryofJekyllIsland/T...
Also, nearby, St. Simon's Island has Fort Frederica which is a neat little place to see, and there is also the lighthouse and it's museum.
http://www.nps.gov/fofr/index.htm
http://www.saintsimonslighthouse.org/lighthouse.html
Oh.. all of the above are less than 15 miles off the interstate. But there is also a train museum in downtown Savannah, but it is more like 30 minutes off the interstate.
ETA: If you do opt for going into Savannah, there are a couple of forts in the area that are interesting. Fort Pulaski and Fort McAllister.
And here's a link to the Roundhouse train museum:
http://railga.com/oddend/roundhouse.html
http://en.wikipedia.org/wiki/Fort_Pulaski_National_Monument
http://www.gastateparks.org/FortMcAllister