I have a Kiefer with empty LQ that I plan to start working on this spring.  It might be another year before I get around to doing the finer details, but I'm still dreaming about what's going in there.  Any idea if you can put a tile backsplash above the counter top without the vibrations of travelling destroying the grout? What about mirror backsplash?  I know I could do a mirror door on a cabinet, but that's a little different, not attached to the wall, and it would move differently.

Also, my dad and I did a simple insulated dressing room/tack in my last trailer, which was steel, and had great results with styro insulation and 1/4" wallboard, but I did wonder later about why we never used a vapor barrier, the way you would on a house? It never caused any problems not having, but it has made me think a bit about whether or not it's a step I should take on this new aluminum trailer LQ.

You can attach almost any product to any back splash by using polyurethane construction adhesive. It will not move or come loose with vibration. Grout as usual and you'll be good to go. It will also work well for a mirror.

Most of the rigid Styrofoam insulations have a plastic covering. This and the foil on the foiled faced insulations are an adequate vapor barrier if the seams are taped.

BOL  gard