Is there a specific reason for not choosing the Florida Connector / Atlantic Coast route? You mention quite a few trails - better for biking? Nicer towns for overnight/camping? I can see the Atlantic Coast being very busy and congested in places. I don't mind cycling in traffic (I'm from Amsterdam and used to cycling in utter chaos) but I definitely don't want to be dumb about it and choose the best route possible.
Maybe cycling from Miami to Fort Meyers over land would give me a nice tour of the Everglades and also a little less miles? Would that be advisable?
I have 35 years of loaded touring experience and tens of thousands of miles. With that you learn what you like. Also, as I have said, I have already done the Florida Connector (FC) and parts of the Atlantic Coast (AC). For the route listed above (which I did a few years ago), I did not want to overlap too much of the same routes I had previously done (except for the Keys which I enjoy). I strive to balance services with lack of traffic. The above route definitely is less on traffic than the AC and since I didn't want to go all the way to Jacksonville just to head west, I looked for a place to break off the FC. However, from Panama City on, the route has equal or much more traffic than the ST, especially around the major metro areas. After a day or two past New Orleans, the traffic drops significantly.
Anyway, I had read a few journals on CrazyGuyonaBike that went along the coast and a few that did the ST. While the ST seems to be a a fine route, I personally enjoy beaches so thought I would hig the coast and if I did not like it, I could break off and head to the ST. Plus I wanted to see New Orleans. Finally, I hate to double-back, i.e. New Roads, LA to New Orleans back to New Roads, so I just researched a route going from New Orleans to Bracketville. As indicated before, there are numerous locations you can break off of either route and go to the other if that suits your needs.
I have ridden the route between Key West and Galveston but due to a family emergency of one of my touring partners, the ride ended there. I have driven the route between Galveston & Bracketville howevere and it appears fine for touring. Depending on your needs/desire (prefer Austin or San Antonio, going to Mexico/south, want to do a more "perimeter tour", etc.), there are a couple of options I have mapped out and/or ridden. Just email me privately and we can discuss further.
Please note that you will need to do slight more hotels on my route compared to the ST due to development and a LOT of campgrounds do not allow tents. Also, the costs are higher since you are in a high demand area. I am blessed financially so that did not concern me but wanted to let you understand the ST is definitely cheaper.
Regarding the Everglades. I rode between Naples and Miami way back in '87. While OK, I would not do again if I could do another route and to me, if you have time and money, the Keys then ferry over to Fort Myers (or even Marco Island if you want more land miles) is MUCH more scenic and interesting. I didn't even see one alligator
so maybe that is why I prefer the Keys. Look at Google's streetview of the various portions of the section between Miami & Naples versus the Keys (especially southern Keys) and determine what best fits your needs/wants.
As a side note, you will have difficulty in places stealth camping in Florida and the Gulf Coast in general due to the swampy/tropical topography and/or development. However, there are more WarmShowers available.
Finally, if/when you contact me privately, please note I travel sporadically about 3-4 months a year so if I don't answer right away that is why but will upon my return as I go through the 10,000 emails that have piled up.