This is an interesting thread, as it makes you think about how to improvise when an emergency for which you are not fully prepared arises. My DW and I make several 'truck camping' trips per year into the Chippewa National Forest. Even though the landscape there is much different than the one described in this scenario, a similar event in my neck of the woods is something we plan and equip for, so we would never be in this sitation under-equipped.

Realistically, I also would not cannibalize my truck in the weather described, as I plan on surviving and the little bit of benefit I would get from ripping out the seat cushions/covers and wiring vs. the $3000 repair bill when we got home would make it a non-starter for me. I would take a mirror and seatbelts though.

I have limited (OK, none) experience in arid mountain camping, but here goes anyway:

Since the assumtion here is that staying put is not the best option, here is what we would do The road pictured is well-maintained and fairly well travelled as evidenced by the half dozen fresh tire tracks in the photo. We drove in on that road and we have a map, we would backtrack that road to civilization, camping at night along the side of the road and hoping to hook a ride along the way. The trip on foot would take us 5 days with good weather and a little luck.

Fire/signaling:

the lighter, matches, left side car mirror, hatchet, knives

Hydration:

T shirt section, 1/2 liter bottles, the 5 gal collapsible, and the coffee pot

Shelter:

Would carry tent depending on how heavy it was (I am a big brute in pretty good shape). If it was truly too heavy for me to carry a long way, would first opt to ditch the steel poles and stakes and carry the fabric. If that option is still not viable, I would dissect the tent and take the largest flat piece I could make, the rain fly, the ropes, and maybe the floor and fashion the screens into headnets. Would carry one sleeping bag (probably the lightest) and the blanket.

Clothing:

Would ditch extra jeans in favor of the heaviest shirts (one each)and socks. Would fashion hats from a pants leg if we didn't have them. Would cut cotton shirts onto bandanas for each of us.

Food:

Would evaluate the food. Carry the lightest most nutrient dense, and eat whatever was in the cooler, or whatever else we couldn't carry before we left.