I put the Bounce sheets in the outside compartments as well...they supposedly don't like the smell so my thought is if they are in outside compartments that aids in repelling them....yes the trailer smells pretty in the spring, but it airs out pretty quickly.
I have heard of people also using bar soap shavings, but that seems much messier and a hassle....easier to just lay sheets all around the perimeter, on the bed, on the couch and in cupboards.
It has worked for us for the last few years, so I just keep doing it.
2011 GMC Sierra 2500HD
2016 Rockwood 8289WS, Diamond Pkg.