Grab a copy of Drive I-95 for your navigator. A great way to find out what's at the next exit over the horizon, and to find out where the radar traps are usually located.
Get the gasbuddy app on your smart phone so you can shop the best fuel prices on the way down. Arrive with a few extra $$ for the park.
If you aren't preplanning your overnight stops (we don't), stop at the state welcome centers and grab the hotel discount booklets. They have great coupons for walk-in rates, but run them against the CAA travel guide or an app to make sure the hotel is okay. I like long distance driving too (ours is about 22 hours on I-81/I-95), but I always stop when I start to feel tired. Not having a reservation means I can go further if I'm not tired, or I'm not pushing to make a pre-reserved destination if I am tired. Arrive alive.
The state welcome centres are great pit stops on the way down and back. I'm pretty sure I've peed in every one from Eastern Ontario to Florida and back. Kind of feels like a dog leaving his calling card in each state. Arrive comfortable.
If you have time, don't forget to stop and see some sights along the way. I don't mind driving endlessly, but DW gets more than a little car crazy, and I have to remember to let her out every now and then. Arrive Married.
Sunday traffic should be okay across Orlando on the I-4, but it at all in doubt definitely take the 417 tollway around Orlando. It starts around Sanford and ends right near the Maingate (South) end of Disney property. Since you have SunPass you can sail right along the whole length. Arrive without Road Rage.
Enjoy the drive and your time when you arrive!
