My wife and I are big fans of dried potato's. The weight differential here would be huge with a big family. You can do everything from hash browns to mashed and scalloped. Sam's has the large square boxes of mashed and Hash Browns.
Dried milk is great for using in cooking, or cups of hot cocoa. You can always get fresh, if the dried doesn't suit their taste buds, for drinking.
Dried eggs, aren't as good as fresh, but for scrambled with some bacon or sausage added, or baking, their great.
When I was young....just after the last dinosaur died,..... we ate everything but the plates when we went camping. Somebody was always ready to eat what we didn't want, if we decided to go hungry(I don't remember this last ever happening)
Think about canned ham also(not spam). It's great when added to scrambled eggs, or sliced and fried with eggs, or added to scalloped potatoes. My wife and I have been buying them at the Big Lots here when they run their big specials. We've canned our own beef before, and found the canned hams to be in the same price range, when all is said and done.
Just shop wisely. Most freeze dried stuff is pretty expensive. Great if your a prepper, but feeding a hungry horde of growing kids, not so much.
...and another thing. With that many mouths, don't be a stranger to a nice cooler, to keep larger meat(and frozen veggies), items in. A little meal planning(what you'll eat first on top, and working down), and not opening it anymore then needed, and the ability to refreeze the blue ice things, and you can stretch a decent cooler properly stocked before you leave, for a week or better. Keep them in the shade, and cover them with a blanket or rug.