I've been pondering the same wiring options myself - join with the original two or maybe divorce them to work just off the switch at the rear... I suspect it will wind up being one of those things I think about way too much ahead of time but finally just do what's simple when actually laying out the wiring comes around. The thought of a door switch for the tailgate or liftgate is interesting, but I've not come across a simple solution thus far. There's still plenty of time at this point, though.I was thinking about that myself, but with a twist. With the gate open and manually turning on the rear slider switch, the existing dome lights come on. I'm at the back and don't need to se up front and light up the entire interior, only the rear area. I was thinking of a rear light(s) independently controlled at the rear and maybe on a door switch so it comes on automatically when the gate is opened.