I used 2x 6ga wire per pole from the panels to the controller.
I also drilled a hole in the roof into the camper (it is a closet in the nose of mine)
I then drilled another hole in the side wall inside the closet and routed the wires in the wall and finally thru a hole i made under a dresser drawer.
Its as close a run as I could make, and saved at least 15 feet had I dropped thru the reefer.
pian: I'm still running a '12v' (19.5) solar panel set and have 500w. I can do 800w on my TS-45, but I would probably upgrade to a TS-65? (I think thats the next size up)