The switch is gonna work out pretty slick. It consists of a round plastic housing with a magnet inside that will push in flush into a round drilled hole on the hinge side edge of the door. And a matching wired switch that will push into the door jamb. The brown color will match pretty well with the color of the door, and look factory. It is only rated for 1/2 amp, but that will work fine to trigger the relay. All this is about a 12' run from where I gotta fish the wires to the slide control switch, which has 30 amps going thru it. The high amp draw is a primary reason I want to go in the relay direction. Keeping high amp draw runs short is most always a good thing when possible in my experience.
Thanks to every one for setting me in the right direction for finding this solution.