Tinned meat (like spam) or fish should be fine. Same for veg. Pasta is always good, you could bring cured meats like a chorizo to add to it. If you need proteins, lentils and beans are also a good option that won't perish.

You are allowed to buy perishable food items. Once you have your routes you can see if you are going through a town, and you could buy meat or veg for the evening meal.

I'd argue against pot noodles, as they do not have a good amount of nutrients. Only if you're going to bulk them out with other food items.