For a car camp sleeping pad, a cheap Costco poly fill sleeping bag over a full size Thermorest or BA pad is the shizl. Have used this arrangement both in my wall tent and Coyote Camping it solo in the bed of my Toyota 4x4.
At elevation, things can get pretty damn cold. I concur on the fleece beanie for around camp and sleeping too. Usually live in a fleece neck gator too. My NF down mummy bag has a nice collar and hood, but the beanie/gator makes the unheated (no CO) sleeping space quite pleasant.
When hunting solo in-state, I usually Coyote Camp to be able to move quickly should the need arise (big snow storms, move with the elk, etc.). Found that using a pop up 10'x10' gazebo with some blue tarp sides provides a good shelter from rain/snow/wind that is much easier to manage on my own than a wall tent/stove/firewood. A couple Rubbermaid totes keep the rodents out of my food/gear. A propane Mr. Heater in the gazebo keeps both me and the water defrosted. It is a far stretch from a wood stove-heated wall tent, but I can be either set up or rolling down the mountain in less than 30 minutes.
