Decided to put a Dometic hardwiring kit in the back. Sorry for the lack of pics.
In the driver's side footwell there's a grommet in the wall for the hood release cable along with another grommet for the rear washer fluid hose. I decided to go through the hood release cable because it comes up behind the fender near the controller which will be used to power the rear. So....
Up on the jack stands. Turn the wheel all the way to the driver's side so I can remove the wheel well liner in the back to get to the cable grommet. Fish tape through the to get the grommet to pull the monster 10g positive and negative cable through into the passenger compartment. Plenty of expletives were used to help with this process.
Once it was in the cabin I ran it under the door sills. If you pull the door gasket off the bottom of front and back doors you can lift the plastic the protects the main harness. There is enough space to run your cable next to the main harness and through the retaining loops it passes through.
Use the fish tape again to get around the B pillar to get to the back door sill. The plastic cable cover in the rear door is partially captured by a fold in the rim for the door grommet. Use a body panel tool to push it away from the rim and from under the fold to lift the protective plastic and run your wire next to the main harness.
The plastic covering the main harness is a PITA to open up and run the Dometic cable through. There was a distinct increase in expletives during these parts.
From there I marked the placement of the hardwire kit on the rear driver side panel and used a step drill to make a hole large enough to get a fish tape down to the rear door sill. Somewhere out on the internet there is an install video of a similar project using a blue sea panel with a voltmeter, USB, 10A plug, and switch. His original plan was using the same placement but discovered there wasn't enough space for the panel to sit flush. The backs of the panel hardware would contact the frame. He had to move his placement to passenger side. Plenty of space for a power cable though.
Home stretch. Cut the cable leaving enough for some play and future changes. Added ferrules to my leads. There is a screw terminal connector on the unit with markings on the board to show positive and negative terminals. Glue had partially covered them on my board so I had to look closely.
Done. Expletive meter now at zero.