***If you pack food that must be warmed up, make sure you include a way to do that. I purchased a couple of Nu-Wick candles and a folding stove. ***
When I was in the military in Alaska (1969) we were told how to prepare for being stalled in sub zero temps in our autos.
We were told to pack...
Two cans STERNO.
Sterno stove.
Matches
candles.
hard candy for calories.
Two blankets each.
Just in case.
I still do that today.
Note: If you buy STERNO, shake the can and see if it sloshes. If it thumps that means the alcohol has evaporated and is no good.
For HOT summer driving my wife and I have small coolers each. We pack each a bottle of frozen water and our regular drinks. The ice keeps the drinks cool and if stalled for a while we can then drink the unfrozen water.
Also, take neck chillers already soaked and cooled to keep the heat at bay.
Candles...check your hardware store for PLUMBER’S CANDLES! These last a long time and burn at a steady rate of several hours. I forgot how long each lasts. They are designed that way so a plumber will know how much time and light he has per candle. The hardware dealer should know how long they burn.
Take a look here