These are some great ideas, we are doing a 10hr car trip with 3 in a couple of months so some good ideas for me as well.

We are planning on leaving pretty early to get through Melb before they are due to wake and have breakfast - so will stop for about an hour - and then try and get to the next stop for lunch after they have another sleep, then a stop for afternoon tea, so hopefully we won't need too many snack during the actual drive part of the trip