State Fair of Louisiana

Don't forget the State Fair of Texas! Get a corny dog, ride the huge Texas Star Ferris Wheel, and marvel at the petting zoo.

Yes if you like State Fairs that is a fine one.  From Dallas I do like to stop in Shreveport on the way to Florida. There's also the Global Power Museum (antique airplanes) at Barksdale Air Force Base. The next stop might be either Mobile or Pensacola and then Tallahassee on the way to Orlando.

Yes, Shreveport would be a good stop if you're driving straight East on I-20. From there, you might go to Jackson (Mississippi) and then end in Orlando.
Starting from Dallas, however, some people recommend you go down to Houston first, then follow the gulf coast along Lafayette and New Orleans, continuing on to Gulfport, Biloxi, and over to Pensacola and maybe Destin.
Shreveport is not near the coast, so I think that's the major decision for your road trip, depending on what other stops you want to make.