We travel with our dog all the time (and our cat). They never stay behind. The cat stays in the camper when we're away. The dog always comes with us where ever we go. We never leave the dog inside the camper alone. We don't think he barks, but we just aren't sure.
Once we did an experiment on the dog. (at home). We put the dog in the camper while we went to Wall Mart (about an hour trip). We put one cell phone in the camper and the other with us. Called and made the connection. We listened what the dog did while we were gone. Poor thing barked the entire time we were gone. So we decided we'd never leave him alone in the camper again. And we haven't. It now been almost 7 years. If we cannot take the dog with us, we just don't go there. If we need to go to a store, one of us stays in the truck with the dog while the other is shopping. We select restaurants where we can eat outside with the dog. It' just NO fun at all for the dog to be left alone. ALL they want is to be with YOU! That's all they want! They don't understand the whole concept of camping at all. YOU are their entire world. Don't make it miserable for them.