I have a Navigator with an aftermarket dvd player that has a backup camera input. I got a compatible camera(just plugs right with with no custom wiring) for it and need to get it installed. I understand that the shop will have to run it from the rear license plate, through the tailgate, and under all the trim or carpet to the deck. How much $$$ am I looking at? I want to know a ballpark figure before I start visiting shops.