I don't know where the thread is, but I installed a Warn winch quick connect power cable from the engine bay to the rear bumper. I put the connector plug next to the 7-way trailer connector. I use it for my dump trailer power boosting during multiple lifts. I tied it an upfitter switch and also wired into the high idle circuit so it would boost output while stopped. I also have a set of jumper cables with the quick connect plug on one end.
https://www.amazon.com/WARN-32966-Qu...MFGE539S5E4GQ0
on edit: I used split wire loom to protect it along the frame. The large fuses should be close to the truck's and trailer batteries to protect both ends of the system.