I installed my camper leveling gauges in the cab of the truck. This way I can see when to stop in a campsite for better leveling.
All you do is get the camper level then glue the gauges in with silicone with the indicators pointing level. Put one on the door, where you can see it, for front to back leveling. Put one on the dash if you like for side to side. The one on the dash is optional. Just about anyone can tell real close if that way is level or not.
When you go to trade in your truck the silicone will rub off.