Southern USA Driving Holiday

Disney Orlando. Pop Century resort is very interesting and affordable in comparison to the others. From there Disney provides bus, monorail, or waterway transportation from one park or resort to the next, all free. Lots of sight seeing without ever entering a park.
Worlds largest collection of toasters can be seen just outside of Columbia SC. You would have to slow down and leave the beaten path to se those sort of things.
Just depends on what you would find interesting.
You may find Daytona disapointing when there isn't a race. Infact if you're not accustom to high heat combined with high humidity you may not enjoy the south at all in August.
I've found mid October the best time of year to travel anywhere.