We have (2) German Shepherds that we have taken camping with us for 10 years. The female's separation anxiety has become worse over the years. To the point if we leave them alone inside the camper and she thinks (or knows) I'm outside the camper she starts whining to the point it sounds like she's being skinned alive.
This is our solution that has helped make our camping trips more enjoyable:
1) Turn the Air conditioner to 65 and make sure the fan is set to constant (for noise so they hear less of what is going on outside the RV).
2) Turn the TV on. It works for us, we sleep with it on and they are always in the bedroom with us sleeping too. This helps create her comfort zone.
3) We give her (2) Benadryl pills about a half hour to us leaving.
4) Take them for a walk, this helps get them tired and gets that Benadryl running its course.
Having a good vet and being married to a Pharmacist has its perks. Our next course of action was another product called COMPOSURE. It's a chewable treat and you can give them 1-4 of them depending on how anxious they still are. Our vet said that if and when the COMPOSURE no longer controls her anxiety that there are other meds (prescription strength) that we can go to.
Don't be afraid to scold them either if you come back and it sounds like a slaughter house in your RV.