Help me plan my trip please! RI, DE and MD

can't help you with RI, but Delaware I would say Indian River Inlet at Delaware Seashore State Park. campground is a little nicer and newer on the north side of the bridge. As for Maryland, I'd go a little further south to Chincoteague, Va. to Toms Cove. I have 2 younger brothers each have their own tt and families, and we use these parks every year. Toms cove does not take plastic. they will make reservations and take a check. have fun.

In MD, rocky gap state park,in western maryland and also a small campground just north of baltimore that has waterfront spots, bar harbor.
bumpy

clarified my post

Normally, I would recommend Chincoteague/Assateague island as others have and then down to Williamsburg Va for the historic areas as well as Busch Gardens/Water Country USA, maybe even staying at Newport News Park.
But we still dont know what will be open, Md and RI are some of the more restrictive states, they may not be good choices this year, or at the least access to many attractions may be spotty.
Since your in Detroit, a trip to the west,, The Dakotas, Mt, even Wyoming may be a safer bet on having your plans stay intact.

Have you been to Washington, DC? There are a few campground options within reasonable distance of Metro stations; the least expensive option is Greenbelt National Park, which is closed to vehicle traffic for some renovation and road work but they say should reopen this spring. Their sites have no hookups. It's maybe a half hour to 45 minute walk to the nearest station. Other good options are Cherry Hill campground (which very much caters to DC tourists and gets good reviews) and the Lake Fairfax county park.

Try booking in RI Fishermen's Memorial State Park and Campground, down the road is the beaches in Narragansett. If you bring bikes, you can bike down the road to the ferry and take it over to scenic Block Island and bike the island, lots of touristy shops and restaurants to get a bite to eat. Day trips to Newport Mansions and Mystic Seaport CT, about 40 minutes away. Check out USS NAUTILUS museum in New London, CT


Assateague State Park in MD, mostly dry camping but does have 2 small electric loops... tough to get a site if you can but well worth it!! Wild horses everywhere, beaches, biking, walking trails and kayaking (rentals)

Mike

Here's one possibility:

https://www.nps.gov/asis/index.htm

Wild horses come right up to your RV.