Motorhomes
Class A, B and C units drive under their own power, so they need auto liability like any vehicle, plus contents and attached-equipment coverage like a home.
Travel Trailers and Fifth Wheels
Towed, so liability generally follows the tow vehicle while in motion, but the trailer needs its own physical damage coverage and its own liability while parked and in use. That parked-and-in-use gap is the one people miss.
Full-Time Living
If the RV is your primary residence, a standard recreational policy is the wrong form. Full-timer coverage adds the personal liability and contents protection a homeowners policy would otherwise provide, so tell the carrier if you live in it.

