You sound like me!! We are leaving in 24 days, driving 21 hours and have 2 adults and two kids, although my kids are 14 and 15 !! We made our first drive when they were 8 and 9, so we have lots of experience. Are you driving straight through, or stopping for a night?? If you are stopping for a night, I would highly recommend a "hotel bag" filled with just the things you need for overnight and put it on TOP !!!
We always have a cooler with drinks and a snack bag..I always open all of the food and put it in ziplocks before we go..that reduces spills and keeps things fresh. I NEVER have any melty snacks..I stick with pretzel sticks, goldfish and some candy like twizzlers that don't melt. Don't overdo the drinks or snacks..we stop a lot which is half the fun!!
A DVD player is helpful..our van has one built in, but the portable ones are pretty cheap. I let each kid bring a pillow, a blanket( it encourages sleeping!!!) and a bag of things to do. I have a thing that attaches to the headrests of the front seat that is just lots of pockets..It helps keep the mess under control. Also face wipes are a MUST in my "car" bag. I also have extra batteries, MOTRIN !!!, tums, bandaids, pens and a notebook in my bag!
Don't forget to keep your camera ready. We always stop at South of the Border for a picture with the gorilla!! Maybe pictures at each state's welcome center??
I keep small garbage bags in the glove box and at every stop we "police" the car!!
One year we collected rocks from every state we went through..that led to one son's hobby of rock collecting!! We glued them on a map of our route when we got home!!
Good luck !! We enjoy the drive so much, and have traditions we always do, like stop at Cracker Barrel for breakfast!! The drive is long, but it can be fun!!
My husband always makes "trip" cd's of music, and keeps track of milage and gas prices..It helps him pass the time. We also like to pick out an audio book we would both enjoy to listen to.