[DutchmenSport]

Others have answered question 1 and 2 and they are correct above.

Regarding question 3?

We use our Montana 375FL (41 feet long - 4 slides) most of the year at home in the driveway and when traveling. This year we were fortunate to take the work-from-home mandate on the road. But even when home, we still work and hang out in the camper, sleep and eat in it, basically 24x7x365 and we live in central Indiana where freezing weather can start as early as November 1 and last until April 1.

Even in freezing weather we use our Montana ..... UNTIL the weather gets cold enough we are running through 1 - 30 pound tank of propane ever 2 days for heat. And that happens when the outside temperatures reach about 20 degrees above zero.

We also winterize when home, even though we use the camper in freezing weather. We "dry camp" and keep a port-a-potty in the bathroom for "night visits" and then take it into the house and flush it there. At home, we also have a septic tank with a very easy removable cap. I can also dump it directly in there too.

But to answer your question about propane usage, you can expect to run through a 30 pound tank every 48 hours when the daytime temperatures reach about 20 degrees.

When that happens, we move back into the house and get all bumbed out!

About the heat going under the floor? About 50% of your heat goes under the floor, but the thermostat is inside the living area. The ducts under the floor come directly off the furnace and run to different places under the floor and are just open ended ducts. They are smaller in diameter than the ones running to the living area of the camper.

Another thing, the chloroplast under your Montana (the underbelly), is absolutely NOT sealed. The wind can easily blow through the cracks and seams and where the J-panel wraps around from the side of the camper to the under side. It took a couple years to figure out why so much air was blowing back UP through the furnace return located on the stairs going to the upper level in the fifth wheel. Once I sealed the chloroplast seams (I used Liquid Nails, about 20 tubes of it), we don't have that cold draft blowing across the lower level floor any more....... also .... the propane usage improved too. There's a lot of cold air that comes through those cracks and seams. I strongly suggest getting some kind of caulking sealer and seal up the bottom. It will make a 100% difference on the cold drafts that come through the furnace return.