Not quite sure if this is the right category, this is more of an accessory than a modification....
We have two 12 volt outlets in our Starcraft 235fb. Both are located high on the wall, one in the bedroom, and on inside a doorless cabinet above the dining table. Clearly put there for connecting a TV. But we go camping to get away from TV. We do, however get warm (well, not today, it is -20 F), so we have some twelve volt fans. Always had to use D cells to run them, because the 12 volt sockets were so inconveniently placed.
But saw this when strolling through Harbor Freight the other day and bought two of them. Just the solution I was looking for. Maybe you too?