Unfortunately not... the issue is the separation. She gets really nervous when left alone outside her home situation. The only alternative to the sedative the vet suggested is a lot of exposure. As soon as the snow melts, we'll start practicing daily, leaving her in her crate in the rv for a short time (a minute or so) and then trying to increase it slowly. I hope this will work.
I think you already know the answer.
We also vacation in our travel trailer frequently, and our dogs have learned that it is just their "other house". Their behavior on the road is pretty much the same as at home... including being happy crated when we have to leave them alone ot go sight seeing, visiting, shopping, whatever. It eill most likely be a bit harder for you, because she already has a history of getting upset, but you can do it! Start as soon as you open up your RV in the spring, and practice for very short periods, several times a day. (Starting with 30 seconds at a time, if you have to). Eventually, she will learn that you WILL return and her anxiety should decrease.
While it won't SOLVE the problem, a DAP plug-in, that releases the same gentle, relaxing odors as Rescue Remedy or Five Flower might help too.
Once she is doing well in the RV, you might want to expand this training, and get her to understand that WHERE EVER her crate is, whether it is your house, the RV, or a friend's or relative's house, her crate is ALWAYS her "safe place". This will stand her in good stead if she ever needs to be hospitalized, or should you ever need to leave her with someone else for an urgent reason.