I'm a fan of KISS philosophy. Water, fire, and Mt. House freeze dried food take care of all my needs when roughing it. Jet stoves are very compact, my stove and canister are stored in a coffee can, the propane-butane mix fuel boils water lickety split too. Coleman makes an affordable canister mounted stove that works just as good as a more expensive brand. This is about as minimal work and long lasting food safety as you can get.
That said, nobody wants to eat freeze dried grub 100% of the time. I use a Lifetime (made in the USA) brand cooler that is about half the cost of a Yeti, and by comparison is nearly 90% as good. If I need to keep things cold, I use ice, when I need to keep things frozen, I use dry ice. My medium size cooler will keep regular ice for up to seven days if I pre-cool it, and cover with a blanket. I have not tested how long dry ice lasts, but it will keep food frozen for at least four days. Just the same as a freezer or fridge, the more you pack it, the more efficient it will be.
Because refrigeration is a limited resource, one needs to consider alternative food staples that are similar to foods you would otherwise need to refrigerate. Here are some alternatives I pack that remain safe unrefrigerated for a a good bit. The following can last weeks without refrigeration as long as stored properly.
Ghee - Made from butter, so it's not exactly a butter substitute.
Lard - Practically lasts forever.
Hard Cheese - Aged Cheddar, Gouda, Asiago, Parmigiano, Peccorino Romano.
Milk - Condensed or evaporated canned, better than powdered imho.
Eggs - Farm fresh unwashed eggs can last weeks unrefrigerated.
Meats - Jerkey, salami, chorizo, summer sausage. Last for months unopened.
Veggies - Onions, potatoes, summer squash, carrots, garlic.
Fresh Fruits - Apples, pears, pineapple.
If you don't have storage space that is room temperature, dig a hole three feet deep in a shaded area. No matter how hot it is outside, it is unlikely the hole will get above 70 F. A 3' hole in the shade will be 10 to 15 deg cooler than surface temp. The only downside, it may attract animals, so covering the hole and airtight containers are a must.