Charleston - more history albeit different than what you will find in Savannah. You could stay at
James Island County Park.
Wilmington -
USS North Carolina - World War II BattleshipOBX - Catch the
Cedar Island Ferry over to the Outer Banks of NC. No suggestions on campgrounds as I stay in the NPS campgrounds which don't have FHU. After crossing the Ocracoke-Hattery Ferry, there is a small but nice Maritime Museum. Further up the coast is Kitty Hawk.
From there you are on the suggestions of others.
Edit: Oops, forgot to mention to watch the westher. The OBX has taken a beating the last couple years from tropical storms, though they usually recover pretty quick.