First is, we have canned goods and dry goods that can feed us (and others) for several days. This includes canned and dried beans, several pounds of rice, and frozen protein (beef and chicken mostly). You can stock up slowly, but make sure you rotate through stuff. Rice is a pantry ingredient for us

Then, we have blankets, first aid kits, and animal supplies for 1+ week. Again, we procured these slowly. I have lots of blankets and linens from estate sales, they don't need to be new but they need to be warm and clean (or clean-able).