Good foods while travelling?

Next week, my hubby and I (and our 5 and 3 year old) are going to be taking a 12 hour car trip to see our new granddaughter (yay!). We want to keep to our eating plan and also save money, so we are going to prepare food to eat in the car. We try to limit stops as much as we can, so we will want most of our meals to be something that does not need to be heated.

For our eating plan, we need to eat about every 3 hours, give or take 30 minutes. We also have some sort of protein with each meal. Drinks are no problem - we will stick to water. We'll bring some milk for the kids at "meal" times, but will limit them to water other than that (less bathroom breaks!). The kids will want to eat when we do. We'd like healthy options for them, but they have a little more flexibility, but we have to watch out for choking hazards and also stick to less messy things for them.

So far, I have for the grownups:
one meal replacement shake
hard boiled eggs for me, nuts for hubby, with a banana
cheese sticks with an apple
and one meal we can warm up while stopping for gas: turkey burgers with rice and some steamed veggies.

So, I need one more meal, and some tips on what to do when we are having the "drive time munchies."

For the kids, they can have cheese sticks, PBJ, bananas, rice cakes, crackers... I want to avoid apples for them, as well as any raw veggies because of the choking hazard. They only like the whites of hard boiled eggs, so they make a mess with them, so that is out.

Any tips?