I would avoid anything that needs to be kept cold. Coolers are a pain.
See if the campground has a camp store and how well-stocked it is. It might have things like milk and eggs.
Also, if you like cute little farmstands, maybe you’ll see some of those on the way.
You can get small packages of things like shelf-stable cheese or mayonnaise here:
https://www.minimus.biz/condiments.aspx
For milk, look in a big grocery story for the kind of small, shelf-stable cartons of milk that kids pack for lunch.
For breakfast, some combination of peanut butter, Nutella and Minimus condiments on good bread with tea to drink.
For the lunch, tuna with Minimus mayonnaise plus some onion on good bread.
For one dinner, summer sausage with potatoes and zucchini.
For another dinner, shelf-stable packages pepperoni or turkey pepperoni with baked beans, or something like African peanut soup:https://peanut-institute.com/recipes/12137/