We did the ride a couple of years ago driving straight through overnight from Boston to WDW with my 3 year old daughter in my Nissan Xterra. We brought with us pillows, paper towels, beach towels as blankets (double duty), a medium and large cooler full of bottled water, milk, our favorite drinks, sandwiches and snacks. Depending on the type of car you're driving you'll probably be stopping along the way for gas every 3 or 4 hours. There are MILLIONS of places along the way to get ANYTHING you might need to make the ride smooth and easy.
You're going to be surprised how easy it is to drive to WDW.
It's No Big Deal, Good Luck All,
Joe