From what I have seen, you need to disassemble much of the rear plastic parts in the trunk to get to both wiring sides by the brake/directionals. Not something easy. I saw a different item that only need to be clipped over the wire and it using the magnetic pulse from the wire to control the trailer lights. So no cutting and possibly attaching them from underneath the car (no plastic removal). My Hyundai Santa Fe Sport was a 10 min job, right from the bottom of the car. Pull out a plug from connector and plug in the adapter, done ! For a Rav4, considered more "off road", you would think it would be an easy job to add trailer lights.
Plus, just for fun, it seems that all the rear hatch plastics has to be removed to get to the license plate lights. You have to be kidding, did Ford design this ? Hopefully it should be easy to get to that bulb, especially that's why cops like to pull you over at night.