We go camping with friends once a year - there are 12 - 18 that usually go. One thing I do is take the frozen chicken tenders, so they act like ice, then stir fry them with onions, various peppers with fajitas seasoning. You can put any vegetables that you like, like pea pods, bean sprouts, broccoli,season with some other spices. Sometimes I bring along Rice-A-Roni to go with it. (It is easier to cook that up than bring all the other seasoning so do it.) You can use steak instead of chicken. I just found that 2 of the 3 pound bags goes a long way and I don't have to cut it up.
When it is just the family I have made spaghetti - just bring along the sauce already made so all I have to do is cook of the noodles and pour the sauce on. You can do the same with chili too. Just have it already cooked - if it is frozen it works well as ice before being cooked.
For breakfast they eat the oatmeal that all you have to do is add water. No left over that way. We also have bagels, toast them on a skillet a few minutes, works well. We get the cream cheese packets to take along. And the small packets of peanut butter and jams are nice to take along too, and packets of string cheese. My husband loves to make eggs in a basket. I have even done french toast a time or two.
Lunch is always sandwiches, because we would rarely be back at the campsite for lunch.
We don't have a camper and have to deal with "bear boxes" so are limited in what we take.