...apologies for not really answering your question but just tossing out how we are going to be handling it...
We are doing Destin for the first time this year. Driving as well. From...you guessed it...Plano.
We plan to do it all in one day with 4 (almost 5 at that point) and 2 (almost 3 at that point) year olds. Last year we drove to Nashville in one day two different times to see the in-laws. Its not for everyone but we just wake up at 2:15AM, the wife and I do final packing / get ready, and then we grab the kids out of bed, toss them in the car and head out by 3:00AM. In theory we want them to then sleep for about 4 hours or so but reality is they tend to get excited after getting in the car and look out the windows for an hour or so before falling back asleep. We then stop one time for breakfast around 8AM and are in Nashville by 1PM. Wife drives first shift (pre-breakfast), I drive second shift (after breakfast). Pre-breakfast they sleep most of the time and once both are awake we can usually just talk to them and they are fine for an hour or so. After breakfast we give them a toy or two to play with for an hour or two and then when they start getting restless...that is when the movies / ipads come out and that can entertain them for the remainder of the trip.
Destin is about 1.5 hours more than Nashville (11.5 hrs vs 10 hrs). I would admit that is pushing our limits but that 1.5 extra hours isn't worth wasting a day / night in a hotel. We will probably add one more stop between breakfast and arrival in Destin but who knows we may not. We are pretty stubborn and our kids know it