Also a long time ago. I have no idea of the route, but my dad was one of those "take no prisoners, you can pee in a bottle, recording his mileage every night" types. It took us 3 days, averaging 9 hours a day.
Seriously, I love my dad but the yearly family road trips were horrific.
I also remember that CAA gave him a nifty little map book with our whole route highlighted - if you're a member, I'd go see them. I also hear that they have decent discounts for Disney, so it may be worth your while to get a membership if you don't have one.