Also, In a lot of tourist places, such as Savannah or Charleston, will have hop on and off tour shuttles you can take from visitor centers. In fact, I was able to get on the shuttle in Savannah from my campground!!
There are a handful of places that i would never drive a motorhome, such as San Francisco, anywhere within 50 miles of Los Angeles, Boston, New York, etc. Las Vegas is easy, as are most cities, however, I suspect that most of what is really worth seeing in this country is in national and state parks, not big cities.