It all depends on the dog. Have traveled with two different Goldens, one at a time. Both about as calm and laid back as any dog could possibly be. We would take them for a walk, then back to the RV, and they both would go curl up in a dark corner of the bedroom and sleep until we returned later, as much as 2-3 hours, and still be there when we returned.
Not all dogs do as well. We have been camped beside people who left their dogs barking the entire time they were gone. Bad for the dogs, and bad the neighbors. If unsure, a pet sitter would be the best option, if available.