Because RV floors can vary in thickness I would set your depth guide on the drill to 1/2" or enough to penetrate the top layer of plywood. Then use a fine blade screwdriver or similar so you can see how thick the foam insulation is in the floor, then set the drill depth gauge to drill just before reaching the bottom skin of the floor.
What depth do you drill to, for a standard RV floor on a travel trailer?
Because RV floors can vary in thickness I would set your depth guide on the drill to 1/2" or enough to penetrate the top layer of plywood. Then use a fine blade screwdriver or similar so you can see how thick the foam insulation is in the floor, then set the drill depth gauge to drill just before reaching the bottom skin of the floor.