When we remodeled the coach we rewired the 120v and 9v that was in the back room. These came from the ceiling and traveled through the existing closets. I pulled everything out of this back room. Cat, my girlfriend is an electrician, and she then ran these two wires down the back wall and into our rebuilt storage box.
We also ran a 12v to the side wall for future outdoor lighting use. If your coach is similar to this Tioga you may be able to pop out the side of the back closet to the outside.
We purchased an older coach so we wouldn't feel weird about drilling holes in it or eventually getting it wrapped.