Most Milton parts available at Northern Tool (and probably Amazon) are US. I bought a pressure switch there that I haven't installed yet (the tank exploded), but I don't think I bought the unloader style.
Their internal wiring isn't heavy enough to draw the power required to start a fire, so they're at least as safe as any stock component in the truck.
Instead of mounting it in the moving door, why not on the back of the front seat, the back of the floor console, or in the rear bench seat...
Be careful...
No matter how "easy" you plan to take it on a winch, you're always going to keep cranking on it until you get unstuck, or something like this happens. OVERbuild it - don't trust something you already know is sketchy.
I just soldered a common 4-pin trailer connector to the CHMSL, and added both the CHMSL & interior cargo light to the camper shell. Even though I used a crappy broken LED floodlight for the cargo area, it still worked great, and was easy to handle. It unplugged easily when I took the camper...
My truck's only problems were dirty terminals, cheap batteries, and those crappy terminal bolts. After I cleaned the terminals, and studded the new batteries, it worked perfectly on the factory cables.
This shows how to replace & solder top-post terminals, but the idea is the same for...
What you're actually doing is "UN-grounding". ;) The first electric circuits were for lighting city streets. Copper wire was new, rare, & expensive, so Tesla realized he could use THE GROUND as a conductor, and only run 1 insulated wire from the generator to the lights. The ground was the...
The trailer DOESN'T weigh nothing, so you'll be FAR over the legal & sensible limits for a bumper-pull trailer. Don't risk it. A TurnoverBall or UnaGoose are quick to install, and you can rent a trailer.
It's VERY common for modern FWD V6 intakes to cover the rear bank - don't think Ford came up with that, or that you can avoid by avoiding Fords. The only way to avoid is to avoid FWDs & V6s. ;)