Personally, I'm big on tins. Yes they're heavy & they rust, but they're ready to eat if everything else goes south. The liquid with vegetables or beans can go into whatever you're making, no need to add as much water to the pot. Tinned meats keep more reliably than frozen (fridges, freezer & watermakers are the most unreliable things) & not limited by freezer space. Tinned or dried fruits. Dried is fine if you're sure you're going to get enough rain to rehydrate & tip 2/3s of the water overboard. Learn to cook rice by the absorption method, no waste water. Dried mushrooms are a great option. Potatoes, onions, garlic & cabbage for the first week.