Done that trip SO many times on both the I-81 and the I-95 way from Frederick to Newnan. Not including civilian vehicles, I've performed that trip well over two dozen times round trip in two different M1009s, my M35A2 and even once in an MTV. If you are going light and they are not expecting bad weather in the mountains, I'd go the I-81 to I-75, it's faster and much less traffic. If your towing a heavy load and/or they are expecting ice/snow in the mountains then take the I-95 to I-85.
I-81 the D-Day Monument but it's off the beaten path.
I-85 the 101 Airborne training area at Toccoa (spelling) GA.
I-95 there is a museum at Ft Lee, VA (near Richmond) but not sure if it is still behind the fence and if so, you might have to undergo a vehicle inspection.
CAF has a bunch of old planes at the Peachtree City Airport and there is a helicopter history group to the east of there which some of their members belong to this website.
Go on down to Benning and see the Infantry Museum (which is located outside the fence, so no vehicle inspection required). It's worth it and is only another 85 miles from Newnan.
There is a science and technology museum on I-75 northwest of Kennesaw which is neat and has a few military items. It is a GREAT museum if you have kids also. My kids had a ball there and didn't want to leave.
