repeat a couple of times.
That will create a square of insulation
As for doors, next care package to arrive, cut the cardboard into strips long enough to cover any gaps, duct tape it to the door.
(you can fix ANYTHING wiith duct tape)
I have no idea if we can control what gets put in those care packages, but, be aware of some clowns who think that claymores are packages for their own private stock of C4.
We had some of those fellows in our unit in Quang Tri, and they would remove the stuff for heat cubes rendering the clay worthless (dumb asses exist everywhere)
Anyway, I’ll talk to some folks and see about having some ‘toys’ replaced with utility items.
Window caulking comes in long, clay like strips and will fill all kinds of gaps. If you’re allowed to, poke your apo address in any of my comment boxes, I’ll write it down and then delete it.
I ain’t rich, but, I can send some useful stuff.
After all, I was an insulator for near a quarter century.

Stay alert outside.