Agree that you should plan your trip knowing that in the Northeast, from Md to New England, most RV parks close between October 15 and Nov. 15th. Most state parks from VA north do not usually offer full hookup sites either, or there are few of them.
We have been RVing along the East Coast for over 40 years. Florida has wonderful state parks, and many of them offer full hookups. Suggest St. Augustine. Very visitor friendly, much to do and so much history to enjoy. Very forgiving for those who do not enjoy strenuous exercise as well. Easy to walk around and enjoy. Same with Savannah.Our favorite. Great walking tours, incredible food (the Pink House!) very walkable and so very friendly. Skidaway State Park=great park with full hookups. Closer is Red Gate RV Park. Yes as well. Charleston is a must see. Take a Carriage ride, great food, enjoy a walking tour with Ed Grimball. Take the boat from visitors center to Ft Sumter.
Lived in Myrlte Beach area for 13 years. Skip it. Total tourism and very crowded. State parks there, however, are great (MB State Park and Huntington Beach SP). Both have limited full hookups and are on ocean side of highway 17.
In NC, try Wilmington area on the east coast, and if you want to go west, don't miss Asheville area. ONe of our favorite places. Good RV parks in area and so much wandering to do!