Don't even try to get around D.C. in a 37-foot coach. While city buses and tour buses exceed that size, the operators know where they can go, where they can stop, and where they are forbidden. In general, there are few places to park, and limited places to just stop. As a family or individual, without a small towed vehicle, park somewhere on the fringes of the metro area and use public transportation to get around.
Same for NYC, Boston, Philadelphia, Chicago, etc where they have decent public transportation. Other places where they don't, I don't know. In Houston, I've never gotten closer than the suburbs, and even those were a challenge. I would park outside the city and have friends come to get me.
