I'm sure you're going to get a lot of interesting comments here. I'm going to add one and a whole another area you hadn't thought about I bet.
I have a 16 ft
Scamp, which is definitely not a All season camper. But I actually end up doing pretty well when I have to when I get go out operational on an emergency. One thing I did find out is that the stamp has a really good
furnace. It uses a lot of
propane though. And it uses enough that the standard barbecue tanks have a hard time in cold weather providing that much
propane that fast. Basically the
propane has to boil off to become gas to get out of the cylinder to run your stove. And put it boils off it cools the rest of the propane and it quickly cools it down so it won't boil anymore.
Now above about 20°, you get enough heat from the atmosphere to keep the propane warm enough to boil off but continuously. But at about 20° you start having problems at the
furnace is using more propane than the outside air can provide in rewarming to the tanks.
The good news is you can buy a little warmer on Amazon that wraps around a tank and will allow you to keep the tank warm enough to keep boiling off propane to keep the
furnace going.
Using this little heater, which does take AC, I have been operational in Sub-Zero weather with the door of the camper being opened a great deal because it was the operation center and being able to maintain a reasonable indoor temperature. Absent that you get about to 2 to 3 hours of the furnace running and then you don't get any more furnace