well you have to ask yourself what kinds of things do you enjoy? When I take my road trip I will be seeing historic sites, museums, botanical gardens, antique stores, historic houses & mansions, parks & food places I've seen on tv.
Stopping in DC has a boat load of museums to check out. If you go through Memphis TN you can stop at Graceland if you're an Elvis fan. VA= Busch Gardens. KY has the corvette museum & the Perryville Battlefield.