It could be a bigger job than you want to take on. It will involve taking the wall panel and part of the ceiling panel down in the slide out to fish the wire through. You will need to remove any cabinet or window that is holding the panel in place. I would go through the sidewall of the slide out as the outside wall is laminated and the sidewalls are hung and easier to remove. the wiring is ran through a track and if you are lucky you may be able to push something like a fish tape through it.