The liability coverage is the same whether car or motorhome - it is simply a "motor vehicle" that is required to have liability insurance in all 50 states. Collision and comprehensive is best written as a specific rv policy, since most car policies specifically exclude the things that make the "home" part of a motorhome. You would be unhappy to get in an accident and find that your TVs appliances and furnishings were not covered. Personal effects, e.g. clothing, cameras and such, are separate coverage in any case. You can add it to your vehicle policy (quite cheaply) or rely on homeowners "away from home" coverage to handle it.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL