Hey, Jeff ... just discovered your thread ...
I used the route you show from Mobile/Pensacola to Tampa, so I know you'll enjoy that run along the coast and through the woods. A short stretch of blah in the middle panhandle when you leave the coast, but still a good route given the alternatives. Outbound time contraints (I had a reservation at Long Key SP) took me to the slab from Tampa to Naples, then again on the route you show outbound from Naples to the Keys. Nothing too remarkable there but I'm sure the best choice still for that leg of the trip.
Long Key SP was a good base on the Keys ... sandy (not coral) campsites on the water, hot shower/bathouse, give it an 8.5 on the SP accomodations scale (higher if it had been farther off the highway). A hard reservation this time of year but check out the Florida SP reservation system its very user friendly. They were booked so solid I was not able to extend my stay even trying to move to a rare 'walk-in' site.
Key West itself is just another coastal tourist town, jammed this time of year, I quickly decided I'd not lost anything there but was glad to have made the visit. Took a liesurely stroll through Ft Taylor, lots of iguanas on the trails there. Several at LK SP mentioned that the botanical garden in Key West is cool.
FWIW outbound I took 29 up through the center of the state (green-line route on your map) which was nice citrus country, a better choice than the basically continuous urban sprawl along the Gulf from Tampa to Naples, IMHO. Very long ago I made annual trips to Daytona for racing, nothing in my memory recommends the routes along the Atlantic - again, too much urban stuff punctuated by long straigh roads for me.
Overall I did more slab than you're planning (good for you) but I've done the stretches between here and NOLA plenty and didn't want to do 98 through NOLA again (BTDT - not a town I enjoy on a motorcycle).
If inclined to aviation stuff, I highly recommend the National Naval Aviation Museum at Pensacola Naval Air Station. You'll need a full day to do it justice. The Battleship Mobile was worth the stop, too, IMHO, better part of a day there, too.
I did the hotel thing except for on the Keys, so can't help with campsirte suggestions along the way. I do find the
"All Stays Camp and Tent" iphone app a great campsite finding tool if you're not already familiar with that one - easy to filter to NF and BLM/COE camps which I recall you mentioning as a preference. Its a regularly updated app and works even if out of cell range since it all loads the basic database to your phone.
I'm sure you'll have a great trip, look forward to hearing about it at Ken's on your return.