Snarky contributions above aside, my truck always has a 96 hour kit. Drinking water is in a 3 gallon jug as well as the water in my backpack; an additional 1 gal jug for is kept for utility purposes, but if necessary, it's potable too. Food is stored in an Igloo brand cooler and there is a Rubbermaid brand container for blankets, tarps, stove, fuel, tools, et al. My GHB is included as part of the kit but not in the container.

Depending on climate -- here, at my destination and en route -- I may carry an additional large duffel which I refer to as my winter kit. Everything in the kit is made for cold weather: head-to-toe (balaclava-to-socks, wool and technical synthetics), insulated boots and a few pair of gloves. The parka I recently purchased became part of that kit immediately after trying it on for fit. If the weather en route is an issue (a mountain pass or three come to mind), the parka goes up front with me. That very nice Tilley ball cap will be on my head.

Besides the staying warm & fed thing, there's communications. To help with that, the Nokia 3310 due to be released in the coming months (2Q17) will go into the kit or possibly into the truck console as a spare. Everything The Telegraph knows and Nokia 3310 comparison, 2017 vs 2000 and Nokia 3310 reboot.... If the new version is built as well as the original, it will be both an inexpensive and rugged emergency back-up.