We have been camping since 2013 with a Golden and three Cavalier King Charles.
Camper is a Rockwood 3025 Wind jammer, 30' of living space. Lots of room.
When dogs are left alone the RV is appropriately climate controlled.
Bark control, TV on (no pet channels) blocks outside sounds.
Food and water.
The most helpful control. I have made window covers 1/2 the size of the windows length. The covers are installed on the bottom half of the windows and are removable. This prevents the pets from seeing out side the RV, but still allows plenty of sunlight to come in.
The window covers are made from attic lover vents purchased from Lowes Home inprovement center. Narrow ones for horizontal windows. Wide for vertical windows. They are almost a perfect fit.
Time left alone a minimum. Nice long walk for dogs before and after being left alone.
The dogs love camping and sitting by the camp fire.