Spam and beans!
Nothing tastes better, at least nothing that can lay in the sun all day and not spoil. :D
Canned chili or spaghetti O sandwiches are great too.
Smear some fresh raspberries in bread too for desert.
I try to get those butter packs in the little plastic containers with the foil seal top. most places that carry restaurant supplies will have them (or ask your waitress) I will pack one butter pack for each slice of bread. I put the bread in a Tupperware container so it doesn't get crushed. You would be surprised how good canned food can taste when it is cooked over an open fire in a pie iron. 8)
Spam is the food of the Gods!!!!!!!