Washington DC National Park
I looked at Cherry Hill, too, and was impressed by the information on the web. My friend, who has a Class C, found a national park, Greenbelt, and said it was excellent. It is in Greenbelt, Maryland, and is 1 miles from downtown, just as Cherry Hill is.
We are taking delivery of our new TT soon and hope to visit there, too. Greenbelt info is available through the national parks website. Very reasonable rates $16, or $8 with np pass), compared to Cherry Hill, but without utilities. not far from metro line, too. They have a dump station, but I am trying to decide on a generator or solar collector for power. I hate to give in, but I think the generator in the long run would be wiser due to the need for ac power.