To just add a vote to what others have told you, I've had good luck with kids with the sort of things you'll find on trailcooking.com - look for the "FBC style" - that's "freezer bag cooking" - which amounts to recepies you can just at boiling water to a bag.

Between that and some well prepared snacks (candy, nuts, dried fruit, sausage, cheese, bars) and maybe even some homemade stuff (any scouter can look up the hudson's bay bread recepie)
and you should be able to keep them pretty happy, or give them enough that they can make themselves happy.

In particular, trailcooking.com is laid out in a way that you could probably get the kids looking for FBC compatible recepies there themselves - probably an easy way to get them involved in it. A picky eater tends to be a lot less picky if it was their idea to make it in the first place.