Not sure how your state inspection works for RV trailers but you may run into a problem where the light mounted on the back of the trailer may have to meet DOD requirements...
I had some mounted just under the rear bumper and they had to be DOT approved lenses and also only come on when the truck was in reverse etc... I did not ask if I could keep them covered and only use at the camp grounds when backing... I just quickly removed them and finished my trailer safety inspection...
Just something to check into before you get too far along...
Roy Ken