As you can see from above there are two grommeted flexi conduits to feed the tailgate, I used right Alb used left. Without either of us trying both its not possible to say which is easier. I went for the right as I had to pull down the door seal on the right anyway to get the fuse box cover off and to feed the power cable up the A pillar. The tailgate seal has light grey mastic underneath. I also removed the plastic trim panel at the top of the tailgate to feed the cable out and cut a small notch in it to reduce the pressure on the cable at the back. You would have to know it was there to find it.
Having got the cable into the headlining space at the tailgate I then used a cable puller rod to get it 1st to the back door then again to the front door, each time making sure I routed it clear of the curtain airbags. Finally I removed the courtesy light to pick up the cable from the drivers door and fed it out on the passenger side close to the radar emitter cover around the rear view mirror.
The excess cable for the rear camera I coiled up and tucked it between two foam headliner spacer blocks in front of the courtesy light.