The Toyota 4Runner has a unique liftgate design that has a power rear window that can roll up and down. This makes it so that we can't actually mount a rear dash cam on the glass itself. With the 5th generation design, the rubber trim on the liftgate is too thin and doesn't offer a good mounting surface for the camera either. This poses a bit of a challenge as the rear camera can come in handy in a lot of parking scenarios.
For this 4Runner's rear dash cam, we took out one of the plastic rivets that secure the headliner and replaced it with a simple nut and bolt setup with a metal backstrap instead. The metal backstrap offers a flat mounting surface for the dash cam adhesive to mount to. This installation requires no real custom fabrication and no permanent modification to the car.
As this mounting position keeps the rear camera very close to the edge of the headliner, the view is excellent. The only thing to note with this mounting position is if you're moving larger objects in the trunk, you'll need to pay attention to anything that might hit the camera. We've attached a screenshot of the rear camera viewing angle.