Regarding the furnace I have read many posts surrounding sail switch or circuit board failure and the difficulties in reinstalling the furnace after the repair/replacement.
Specifically getting the exterior exhaust pipe to line up when sliding the furnace into the compartment. If you are one of the lucky ones who has the exterior access panel Hooray and no need to read on unless this interests you.
As I missed the outside access panel by days on my 2018 5.0TA I decided to remove and reinstall the furnace while at home to see what would be needed if I had to do this on the road on my own.
Long story short to reinstall the furnace by myself I removed the exterior metal exhaust pipe/plate as shown in ETI's how too video, but did not need to remove the black plastic insert as Reace did in his video.
Prior to reinstalling the furnace I reinserted the exterior exhaust pipe/plate back into the hole and slide the furnace back in making sure the exterior exhaust pipe/plate cleared the large hole in the back plastic plate on the back of the furnace.
Next I pushed the furnace in further until it was up against the back of the plastic insert. Going back outside and using a flashlight I lined up the exterior exhaust pipe/plate with the pipe in the furnace housing and reinstalled the exterior exhaust plate with the 4 screws.
Going back inside I pushed the furnace back until the front mounting holes lined up with the furnace mounting brackets and reinstalled the screws. Only thing left is to reseal the metal exhaust plate on the outside.
For those who will have or can find someone to help you will not need to remove the exterior exhaust pipe/plate as they can look down the pipe while the person on the inside slides the furnace towards the exterior wall.
Associated ETI how too videos.