Here are some pictures of my recent changes.
The old furnace compartment was a complete disaster, why a vented exterior cover when most units have a solid cover with just the vent ports. It was extremely dirty, took a good hour of cleaning before I proceeded with anything else. There wasn't any way to save any furnace components, the dirt ruined everything. I loved how LL bundled the wiring from the furnace and thermostat. I didn't want to manipulate the LP hose after capping the line, too cold and pretty well static in that original position. Will secure a bit better when things warm up.
Also, the thermostat wiring is run up through a cut out in the aluminum extrusion framing with no loom or protection around the cut out, definitely a risk of damaging and shorting out those wires. If your furnace stops working that could also be a potential cause.
Water was accumulated at the bottom of the exterior cover on the inside, you wouldn't be able to see it unless you removed everything. Definitely would have rotted out a stick framed trailer. Not sure how it penetrated through, but it did.
The new black exterior coupler has a magnetic connection for the cover and also to connect the intake vent duct. Easy and extremely solid to use.
Still a bit more to do, finish the ducting vents, remove the old thermostat, secure the old wiring, insulate under the fridge with some AFB and run the new wiring for my additional exterior fridge compartment fan. I might also insulate the interior 3" vent ducts, but, I kinda like that radiant heat circulating in that area.