Real hard cheeses keep well even in the heat as does hard salami and pepperoni. They may get oily and look terrible but remain edible. They add a lot to simple dishes like ramen noodles (I don't make mine soupy) or eggs. Hot sauce helps too.

Bags of shredded cabbage keep pretty well and are nice for wraps and so on. Foil packs of chicken, tuna, salmon, and individual serving spam are all handy for use with pasta, rice, quinoa, or just by themselves.

I don't tend to do a lot of real cooking on tour. I am a good cook and capable of it, but tend to ride long days and seldom want to make the effort. For my camp cooking, I tend to eat a lot of simple one pot dishes, but splurge on something nicer once in a while. When close to a store a frozen pasta dish, bag salad, and small bottle of wine is a nice treat with very little effort in cooking.

I agree on the powdered whole milk suggestion. Look for the Nido brand if you have trouble spotting it on the shelf. It is sometimes with the international foods and sometimes with the other powdered milk.