First Big Roadtrip with Kids!!!

Well, next week we are taking our first major roadtrip with the boys! We are driving to Iowa for Hunter and Evan to see their Great Grand. We flew out there just over a year ago for Hunter to meet Grand and now it is time for Evan to meet this very special family member. I am so excited for this trip but terrified of the drive! Any advice? Yes, I know some of you instantly thought for us to invest in some earplugs - done! Any other tips? I am beginning to get things together this week for our drive. So, any ideas would be greatly appreciated! We already have a DVD player with lots of new and old favorite DVDs, some new toys, lots and lots of snacks and that is about it for right now. We do have stops mapped out for along the way for fun breaks. We are planning on stopping in Chicago to visit the aquarium which we really think Hunter will love! So, please, offer any sanity saving tips that you may have discovered on your own trips! Thanks!!!