Definitely get each child their own DVD player w/movies they each like.
This is a lifesaver!!!
I buy a new little fun item for each child on every trip so they have something new & exciting to open. It can be a toy, gadget, gift or whatever.
Stop often to stretch their legs.
Map out driving 8 hrs a day.
Bring a small gift for hubby to open so he knows how happy you are that
he is taking this trip with you.
Play games on the way. The best one is a visual scavenger hunt you play for 15 mins at a time. Look for certain big items from the car that the kids check off (red big rig, yellow car, orange construction cone etc). The first one to get all 15 items gets a prize, the other child gets a smaller consolation prize.
I am w/the poster that said get takeout & eat at a local park.
Bring an ice chest w/bottle water, drinks etc.
Bring plenty of snacks to eat in the car.
Pack magazines, books, ipods w/earphones etc.
Bring blankets.
Stretch your legs often.