New (to me) Lance 815 truck camper owner. Got a few q's

As long as its not resting on the bed rails I don't worry about it. I do want 3-4 incles of clearance between the truck cab and the cabover section of the camper (frame flex).

typically you take off the tailgate and put it in the garage.

campers weigh well over their tagged weight ( which doesn't include options like AC, Propane, Water, Microwave etc).

Stay under the tire rating per axle. You probably will need something to help with the suspension but maybe not