We are a follow form policy so it would depend on how you have it written on the underlying policy especially if you are using carriers that differ between the two. Overall though, this is how we distinguish between drivable and non-drivable campers when evaluating liability and classification for umbrella coverage.
Drivable campers (such as motorhomes or Class A/B/C RVs) are considered autos, as they are self-propelled, registered for road use, and require their own liability coverage similar to a standard vehicle. These units should be included in the personal auto count when submitting for umbrella consideration.
Non-drivable campers (such as pull-behind travel trailers or fifth wheels) are classified as recreational vehicles (RVs). Although they are not driven, they can still present a liability exposure—especially when parked and in use. These units are typically not included in the auto count but should be scheduled separately if coverage is desired under the umbrella.