Once your dog considers the camper "home", and is comfortable, he will probably act as he does at your home. If he barks there, he will bark in the camper. My dog started out camping as a puppy and is used to the camper. He doesn't bark at home, he doesn't bark in the camper. I took him up to a motel room one night and went down to get luggage and he started barking right away, which surprised me. I don't leave him alone in the camper much, unless I'm headed to the bathroom or showers. He just sleeps while I'm gone. If I leave the campground, I take him with me. If I think the car might get to warm when running into a store, I park beyond others and remote start the car so that the AC is running. When I stay at a motel, he stays in the car until I'm unloaded and then he goes in with me. He is first out and in the car in the morning and then I pack up. No barking as the car is "home" too. Get him used to the camper before you even leave on your first trip - a bed, a bowl, toys. He'll catch on.