I hunt a lot in North Central British Columbia, Canada and I am always in snow/temp conditions you just described.
I wear snow shoes and always carry a pack for extra cloths and my hunting/calling gear.
I'm 6'3" tall and weigh 215lbs so with the pack and rifle I am weighing in at 240 - 250lbs so I now wear 36" snow shoes.
For a seat I have a single legged fold out seat that I bought when I was in Slovakia that I sit on or one of these new cushion/back rest seat that fold together.
I sometimes set up the folding seat onto my snow shoes so I don't sink into the snow.
I either carry a tripod shooting rest or a bipod made out of wood that I bought from the local wood shop.
I was out last Thursday and got into about just over knee deep snow but had not brought my snow shoes so the only way I was able to get around was walk along snowmobile tracks so I only sunk in about 6" with each step.
I have a light weight tree stand that was designed to be packed in so lately I have been thinking about setting it up in a tree but only a couple feet off of the snow so I don't have to put steps into the tree.
Here is a pic of my last cold weather coyote it was -34 degrees Celsius it was so cold that any moisture in the air was crystallizing I spotted this guy @ about 400 yards made a couple calls on a Primus Ki-Yi call and sat back as I watched him run like a rocket right at me he stopped and sat down facing me @ 40 yards.
I left him at the fence line for about one hour I went back to get my camera when I got back he was frozen solid...