I know this is a cat/trailer question but this may help....
I've had two motorhomes with my cat. The first was a front engine gasser and the cat headed to the back bedroom as soon as the engine started. The second was a pusher, he headed to the front of the coach when it's engine started. He was not under any apparent stress in either coach but clearly preferred being "away" from the engine noise/vibration. Oh, he also did not move around much once we were driving - just slept. I'm fairly sure all cats are different so choose whatever yours finds the most relaxing.