No actual personal experience, but lots of reading. Seems that most folks recommend constructing a simple, "T" brace to place between the floor and the ceiling while you are renovating the closet and/or kitchen cabinets.
Regarding
painting the inside. The rat fur in Scamps and the Carpet in Casitas serves several purposes, nice appearance is only one. They also add insulation, block
light so you don't become a glowing silhouette at night when the
lights are on, and, very importantly, they prevent severe condensation on chilly nights when your breathing inside the trailer will condense on the cold walls and ceiling.
I'm sure others with some first hand experience will chime in soon. Good luck with your
renovation.
Edit: Disregard part of the above if what you meant was that you were cleaning and
painting the foam insulation that is in your trailer. Sorry.