There are very few ocean front campgrounds on the east coast - most are inland. However, there are a few in NC, and Cape Henlopen in DE, and I believe one in FL. Due to storms, evacuation, etc., it's not in the best interest of the campers to be directly on the ocean. There are quite a few campgrounds within easy access of the ocean in Cape May, NJ.
Know of lots of oceanfront CGs. But Can't think of any walking distance to a town. Except maybe Edisto Beach SC. Great State CG on the beach, and right across from the main part of Edisto. But there ain't much town there. A Piggly Wiggly, pier, and a few restaurants.
There are several on the OBX of NC. But I don't know how close to a town. There is one on Emeriald Isle, May be close in, and one on the beach TopSail Island NC. Not close to town.
There are 7 beachfront CGs around Myrtle Beach SC. While they aren't close to town. 5 of them are self contained CGs. Meaning. Once you get in. You don't have to leave unless you want to. Most have minigolf, pools, snackbars, and grocery stores inside the CG. These 5 are huge, and very nice and are towns in themselves.
Google Myrtle Beach CGs. You may find what you want.
You can go to each states visit site, and probably find all the CGs in the state. Like visitnc.com
Cape Henlopen is a nice state park (water, non electric sites) It is right down the street from the Cape May Lewes Ferry, and about a mile from the town of Lewes, which is a beautiful beach town. It is a great area to bike ride and even take a walk to town without getting run over. Rehoboth is about 6 miles away, but traffic can be very bad at times. If you take the Garden State Parkway down and take the ferry, you will have a nice 70 minute cruise to Lewes and a 1 minute drive to the CG from there.
Don't like the view?? Then change it and Go Camping