These small portion sealed packs are a great idea if you can't or don't want to use the fridge.
I can understand the issue with the fridge if you just want to grab the truck and go. I too wouldn't want to run the fridge 24x7 - not for any technical reasons, but I just wouldn't want to waste LP or electricity running it.
We have a compressor fridge now so we can switch it on at a moments notice and it gets cold in minutes, but that type of fridge isn't ideal for those who boondock for long periods without plenty of solar - everything is a compromise.
I like the idea of using it as a cool box. Sally often vacuum seals and freezes meals - I guess you could do the same with water to make a ice bag. Or use those plastic blocks you freeze at home and then put in the fridge.
With an absorption fridge I guess you could kick-start it using ice / frozen blocks but turn it on when you set off on your journey - that way by the time the ice had melted the fridge should be up and running.
Steve.