Lasagna is a good make ahead for an easy dinner. You can bake it in most bbq's now. There is always the hot dogs and hamburgers with watermelon for later. How about making some nice macaroni and potato salads ahead. They keep well and go a long way. Buy lots of fresh fruits and veggies and cut them up for snacks. Kids need lots of milk to help them grow so don't forget that!
I love haystacks! It is a make your own plate type meal. You cook white rice, and open a can of pintos and stewed tomatoes and heat, then you shred lettuce and cheese. Oh and a big bag of fritos corn chips.
The order you pile them on your plate is, corn chips, rice, cheese, tomatoes, beans and then the lettuce. Then you can use taco sauce or salsa.
So yummy you won't want to stop eating it.