There have been a lot of good ideas and quite a few laughs in this thread and that's good.
However, I think the concern for Slowcowboy, in this thread, is for ice fishing; and, for Hunter (best guess: who hunts), found in this thread:
viewtopic.php?f=2&t=57584 is that they need to find ways to keep warm in the snow in areas where there isn't electricity available.
The way I see it, these people have access to:
- Generators for electric power; but, they'd have to carry a lot more gas to power them than they'd probably want to.
- Battery operated 12 volt power, which may be limited
- Wet cow chips

(Sorry...couldn't resist)
- Dry, brought-in wood, which will only heat the outside and shouldn't be left unattended while someone sleeps.
- Propane, which may also be in somewhat limited amounts.
I think the point is to stay warm through the night and heat the cabin quickly to get dressed in the morning. To that, I'd say:
1) Insulate all sides, top, and bottom of your trailer.
2) Hang quilted fabric over doors and windows, to further insulate and to help prevent drafts. The quilts will also help by absorbing moisture condensation, to keep it away from the 'in’ sides of the trailer.
3) Have a really good, probably for sub-zero weather, sleeping bag; and, if it's old and/or packed down, purchase a new one. Once the filling in a sleeping bag starts to pack down, it loses its ability to retain heat because the air pockets within become smaller.
4) Wear winter-rated long john underwear and maybe a sweatshirt as well, and smart wool (i.e. merino) socks. Wool retains heat even when it is wet.
5) Wear a stocking cap on your head. This is because much of the body's heat loss is through the top of ones head, especially if the body is in a sleeping bag.
6) Dirt and bugs be 'danged', if you have a hunting dog, sleep with him. Dogs are great four-legged fur heaters. You can put a sheet or something over your nice new sleeping bag to keep it from getting dirty and the dog can sleep on that.
7) If you can get one, get a good 12-volt heated mattress pad. Plug it in and heat your bed before crawling in at night. Turn it on as little as possible and turn it off as soon as the bed is warm, to conserve your battery. As a safety measure, do not sleep in the bed with the mattress pad plugged in, especially if it is 120 volt!
'8) If you have a galley hatch, close it when not in use. It will not only help keep critters away but also add an "attic" of sorts to help keep heat from the cabin from escaping. Insulating that closed hatch's underside will also help.
9) If you can, add a pass-through to the galley from the cabin so that you can open the pass-through in the morning to make your coffee/tea/hot chocolate, etc. You'll be amazed at how much warmer your cabin will get just from heating water to make your morning beverage.
10) If you can safely do it, use a propane heater, either a built-in unit or a tent-approved model. Keep these away from sheets, quilts, curtains, clothes, etc as you don't want to start a fire. You may want to dedicate a corner of your trailer and build a special cabinet or shelf for it, to further protect against fire. Use the heater only when you are awake, maybe for a little while before you go to bed and again, when you awake in the morning. Also, remember that using this heater may require some proper ventilation, such as cracking a window slightly open. A carbon monoxide detector is also a good idea.
.....Does anybody else have any ideas to add for camping in really cold weather when out in the middle of nowhere?