Cold camping in Colorado

As a prospective TM owner, I am curious how TMs do in the cold.
We were in our pup this past weekend. Night temps in the 20's and 6" of snow outside. We had an electric heater going on 'medium' all the time. It did ok in the day, but the furnace would kick on when the inside temp dropped below 55 (at night). We would like to extend our camping into October, but it gets a little nippy up here in the mountains by then. So, my 3 questions (for now) are:
1. Do the bunk ends on the TM get colder than the rest of the unit like on a pop-up?
2. With 6" of snow on top of the unit, I assume I would have to find a way to get that off before closing down. (?)
3. Is the plumbing insulated enough to keep it from freezing (ours got a little ice in it this time, but cleared out when running the pump a bit).
Your facts (and opinions) are appreciated!