I don't know how high up your elevation is but if you hit time periods in the winter that are just unbearable, it might just be a good time to visit friends, family, and/or warmer climates.
I saw after I posted that you have lived in tents etc before. That kind of experience is so liberating to the mind and body.
It's not something that can be explained in less than 1000 words though so suffice it to say, " I know you know"
I wonder how much can be salvaged from the mobile as far as building supplies and appliances go.
Plus at least you'll have electric. And running water.
I vote for the tree house asap ... if you need a refresh on why that is obviously the first most practical dwelling ... as I do ... we could check with the Swiss Family Robinson ...
Bears? Would bears be a good practical reason?
A tree house fort?
Avoid some snakes? (Live with others, but are they less poisonous? )
Cooler.
A cave for winter could become your food/wine/cheese cellar later.
Okay :-) one thing I'm sure of, the sky's the limit!
Have fun
I'm not far above sea level and Arkansas winters are pretty mild. The highest elevation in Arkansas, which happens to be a few miles from me, is just under 3,000 feet. I've got electricity, so I'll be warm enough unless the electric goes out. And if that happens, I have a relative about 40 miles away where I can crash if needed. All good suggestions on things I need to think about, thanks.
Even if I never live in it, I will make that mobile home useful since it already has electric and water. I won't be heating and cooling it, that's for sure. The living room can be a workshop and tool storage, etc. The kitchen sink can still be used along with a washing machine / laundry station in there. The big bedroom in back might make a good baby poultry brooding area until they are big enough to go outside.
My younger self would've loved the tree house, that would've been fun. Still plenty of other fun to be had, I'll make sure of that :)