We drove in February of last year for the first time. We stopped in New Orleans over night and in Panama City, Florida over night. Coming back we stopped in Mobile (almost exactly the mid point) Our kids were 2 and 4 (they turned 3 and 5 at WDW) and we spent two weeks at Disney.
When we returned in July we drove straight through. We left around midnight and arrive around 4 pm. The trip was a total surprise for the kids. We drove the entire way there without telling them. When we arrived we acted like we were lost and needed help figuring out where we were. They saw the entrance sign and were completely beside themselves! It was the best surprise ever! Coming back home we stopped at Mobile again. I put together fun travel notebooks with dry erase car games, scratch off tickets for fun prizes and treats, and coloring pages for each state we went through.
In March we plan to leave around 3 am, putting us there around 7 pm. We have 8 am breakfast reservations at MK, so it will be unlikely that we will go to a park on the day of arrival.
For us, driving just makes sense. We have a Prius. Last year it cost us $86 each way to drive plus one meal. We packed tons of snacks and water. This year it will be even less with the low cost of gas! We could fly...but that would be $2000 taken away from park splurges!
Dis-Friend 
Buda TX Here (15 miles South of Austin) 
