Key West - never been there but is on my list.
Upper Michigan - been there many times - well worth the trip. We stayed at Munising and Mackinaw City. Driving through the UP again on the way home.
Upstate New York (Adirondacks)- Close to me and been there many times - I can give you recommendations on places to stay.
Hershey PA (still not a destination), We stay at Hershey High Meadows CG.
Gettysburg - Not on your list but I would add it. we stay at Round Top CG. Watch the movie before you go - will make the trip more memorable. We have been I think 6 times - great place to take our children and grand children.
Williamsburg, We stayed at a campground near there - don't remember where. Did enjoy the trip/stay
DC - we stay at the Jellystone CG in Hagerstown, MD. drive to Silver Springs, MD and take the train into the monument area.
Yellowstone...and more. We are taking 3 weeks and some for a western trip(doing it now)
Places we visited and places we stayed at that I could recommend:
First stop was Sauder Village in Ohio - broke up the trip to Iowa. We have stayed there before and toured the village. My wife was a a rug hooking convention there. SPENT 1 NIGHT.
VESTERHEIM - THE NATIONAL NORWEGIAN-AMERICAN MUSEUM AND HERITAGE CENTER, Pulpit Rock Campground, Decorah, IA. (wife and I have relatives that settled in Minnesota that were from Norway - visiting this was on her bucket list). SPENT 2 NIGHTS.
Mount Rushmore, Devils Tower, Crazy Horse Memorial - Rapid City KOA, Rapid City, SD SPENDT 3 NIGHTS
Yellowstone NP - Rocky Mountain RV park. Garnier, MT. SPENT 3 NIGHTS
Glacier NP - Mountain Meadow RV park - Hungry Horse, MT SPENT 4 NIGHTS
Visiting relatives in Detroit Lakes, Minnesota - Country Campground - Detroit Lakes, Minnesota SPENDING 6 NIGHTS
Our final place to visit will be Mackinaw City, Michigan. We will be staying at the Mackinaw City KOA. SPENDING 2 NIGHTS.
Still not home (another 1300 miles from home) and have put 4801 miles on our truck and 3839 miles on the camper.
I turned 62 while on the road and picked up my Senior Pass - only $10.00 and good for life. So we did not have to pay the entry fee into Yellowstone and Glacier NPs. I picked my pass up at the Black Hills National Forest Mystic District visitors center in Rapid City, SD