leaving dog in RV

As others have said spend as much time with the dog in the RV. Before you leave your pet inside alone for an extended period of time do several trial tests runs. I would go outside and sit in my campsite for a few minutes and go back inside. Repeat this several times on several occasions staying outside for longer periods of time each time. This way your pet gets used to being inside alone and knows that you will always come back. It also gives you an opportunity to listen if they bark while you are gone (outside).