We tend to stop often at the rest areas. We leave about 4:30 am (central) and arrive at Pop about 2pm (eastern). With our stops, we take about 8 to 9 hours. It depends on how restless the little one gets and how tired I get! For us, its cheaper to drive than fly. To fly out of Montgomery, we'd have to make a stop in Atlanta, change planes and then fly onto Orlando. The other option would be to drive an hour to Birmingham and catch a direct flight on Southwest. After doing all that, the cost to drive is less than the cost of plane tickets for 3.
However, we have taken 13 hours to get there. Our car started acting up in Gainsville. We couldn't go interstate speeds and went the back way. We got as far as Lady Lake and the car wouldn't go over 20 mph. We stopped at a hotel, called Onstar and arranged for a tow. This was a Sunday, no rental car places open and a ways from WDW. So, we called a few taxi companies and no luck to get us to WDW that day. We tried a limo company and lucked out. We arrived 13 hours later at AS Sports in a limo. Later in the week, we rented a car to pick ours up from a dealership in Leesburg and had a wonderful trip! It was an adventure, especially with a 3 year old.
