>>2508703double up on your sleeping mats: one closed cell foam then an inflatable on top. use a roomy down mummy bag rated for colder than you expect, sleep only in dry baselayers including a toque (not the ones you've worn all day, have a separate set for sleeping in). wear a pair of loose, very high loft thermal socks. drink some hot chocolate and eat some trail mix before bed. fill a naglene or two with hot water and use them to heat up your bag before you get in. use an old gatorade bottle to piss in so you don't have to get up in the night. candle lantern or isobutane lantern that you can hang up so it doesn't get knocked over
