For me, Florida made a pretty boring drive. The Everglades are all fenced off so you can see very little. Drove down from Orlando to The Glades and back all in a day, the only thing of interest were a huge lake and dam constructed and maintained by The U.S army and a handful of alligators . Cape Canaveral was pretty cool though, went there twice and got inside a full size shuttle mockup. Didn't really like the weather either, hot and very humid with a huge thunderstorm every day. Never been to Texas so can't comment on that.
I've also driven San Diego to Los Angeles and I've done both the coastal and inland drives L.A to S.F. The best driving roads though are all well inland, lots of great routes in Colorado including the Million Dollar Highway, Monarch Pass and Pike's Peak Highway.
Pete