Liability, on the road and at the campsite
For a motorhome, liability pays for injuries and property damage you cause while driving, exactly as it does on a car. For a towed trailer, the tow vehicle's policy pays on the road because the trailer is an extension of it. Both types need vacation liability, which pays when the RV is parked and being used as a residence: a guest who falls on the step, an awning that blows into a neighbor's rig, a campfire that spreads. An auto policy has no answer to any of those.