We drove the stretch from Austin to Orlando last March - April.
Total drive is about 20 hours - works best when spread over 2 days.
The first day we did Austin to Lafayette because we got a great deal on hotwire for the Hilton Lafayette towers - 59 bucks, original price was $99. The beds were sooo comfy! This is an older hotel that just underwent a 10 million dollar renovation.
The second day we did Lafayette to Gainesville. Again, used Hotwire for the La Quinta which was like 43 bucks. The original price was $125. Gainesville is 2 hours outside of Disney so if you get up early, you can cruise right in, check-in early, and enjoy the whole day at the parks. The La Quinta is pretty nicely located - close to the highway and a Whataburger right across the highway.
Admittedly, the first day drive was probably a bit too short, the second day a bit too long - just depends on where the good hotel deals are. Baton Rouge just seemed too expensive. That schedule got us into Gainesville by dark.
I used the 1999 RandMcNally Tripmaker software and it has a gas cost section where you input the price of gas and the miles per gallon your car gets and it tells you how much you'll spend for your trip.
One thing to note: the price of gas goes up the closer you get to Florida.
I would highly recommend taking a rental car and get the collision damage waiver if your insurance won't cover rental cars - we got our car backed into last year at Epcot by someone who wasn't looking. It took nearly 2 months for us to get our car back because it wasn't safe to drive back to Texas. For 2008, we are either taking a rental car or flying.
We had an ice chest with wheels and this made it very convenient to fill the ice and save on drinks. Also, portable dvd player for the kids is a must! It kept them sooo quiet.
Good luck and please share any tips you have and deals you find
