Greenville, SC to Boston, MA

On the way home, go from Boston to Cooperstown (New York) and this will get you over into the mountains so that you may be able to see some fall color.  From Cooperstown go down US 15 along the river around Selinsgrove to Hershey (which smells like chocolate and is an interesting town).  If you are there on Friday, Saturday or Tuesday you might divert to the Lancaster County Farmer's Market and you can also visit the Amish country. Then go down I-81 until you can access the Shenandoah National Park, Front Royal Entrance Station which will link up to the Blue Ridge Parkway.  This will take you all the way down the mountains until you are in Asheville and from there you can go home to Greenville (South Carolina)

Continued - From Edenton go to Elizabeth City  This is where a lot of the sailboats going south for the winter on the Intercoastal will be at the free docks. Route 17 follows the Dismal Swamp Canal and at the border of Virginia there is a Visitor's Center which is both for the boats and the cars  (incidentally you could also have gone up the Outer Banks but that would involve more ferries)
From there go up to Norfolk  Lots of things to to and places to see there Portsmouth (Virginia) (access by ferry from Norfolk), Virginia Beach, and the Cape Henry lighthouses on Fort Story
Here you have a choice - you can go across the bridge tunnel to Kiptopeke and up the eastern shore to Ocean City (Maryland) and Lewes or you can go across on US 17 and visit Newport News (which has an excellent Maritime Museum, WilliamsburgYorktown and then tollow US 17 up until it joins US 301 and at Dahlgren crosses the Potomac.  You could then go to Annapolis and cross over to the eastern shore to Lewes  Take the ferry in Lewes across to Cape May and then you can drive right up the coast of NJ.  
I don't have any good options for getting through NYC but follow I95 up to New London (Connecticut) and visit Mystic Seaport  THen cross to Newport before you get to Boston

OK you  can do this. From
Greenville (South Carolina) drive over to the coast Georgetown (South Carolina) would be a nice litle town to aim for or Murrells Inlet where you should be sure to visit Brookgreen Gardens.  Then follow US 17 north - this goes along the Intercoastal Waterway, through Myrtle Beach, and Little River  At this point you could take a ferry over to Bald Head Island if you wanted to.  Instead take the free NC ferry over to  NC Aquarium at Fort Fisher which has both an acquarium and a nice state park about the civil war.  You can pick up US 17 again and go to New Bern which has the rebuilt British governor's mansion and a bunch of other historic houses.  Continue on Rt 17 through @Edenton.  At the time of the Boston Tea Party, the ladies of Edenton had their own tea party.   (to be continued)