I installed closable vents in the bedroom thinking I could close them and let the bedroom a/c cool the whole coach. It kind of works.
What at I found is the a/c runs continually (when the bedroom vents were closed) and was not doing the job we wanted.
So I blocked the common two vents (ducts) that connected the two a/c units. One in the bedroom and the other in the bath such that it is cooled by bedroom a/c.
What a pleasant difference. Bedroom unit turns on and cools the bedroom/bath then shuts off. Same with living room unit. I got to thinking the coaches thermostats are set up like a zoned system but the zones are cross connected such that when the living area calls for cool some of it runs off to the bedroom....so living room unit runs and runs not being able to do the job it turned on to do.
There re is no way around the noise but by blocking the ducts each unit runs less and we get more effective cooling.