We used to camp 3 or 4 weeks a year. Suppers were often one of the box mixes like chicken or hamburger helper, or a noodle side dish mix, with a can of tuna or some chunks of chicken tenders, or even canned chicken. Lunches were locally bought bakery bread, locally bought cheese, some fresh apples, and a pocket knife (often on a hiking trail.) Breakfast was instant oatmeal or cheese grits on getaway mornings, and pancakes or eggs on longer ones.
One of our favorite meals was hamburger, beans and corn. Those were the only ingredients. Brown the hamburger, dump in a can or two of corn and some canned beans, whatever you like, I like navy or great northern. Amazing how good that tasted outdoors.
For a 3 day trip you can freeze cooked chicken pieces or raw hamburger and put it in the ice chest. It will not stay frozen but will be good for 3 days with plenty of ice.