Hotel near train station

If it were me, I would stay one more night in my Sorrento hotel and relax. Get up in the morning, go to Naples and then take one of the numerous trains that head to Florence. Trenitalia goes pretty often - like every 30 minutes on the date I checked and you're to Florence in under 3 hours. No need to move to a new hotel in Naples for one night unless you're dying to stay there.

Starhotels Terminus is right across the street from Napoli Centrale, I stayed there when Terminal 3 in Roma burned down and I couldn't get a flight, so I took the train to Napoli. My usual B&B was full, Terminus was very comfortable.

I'm in agreement with Valerie.
If you are staying in Sorrento already, why going through the trouble of a hotel change?
The morning of departure, simply go from your Sorrento hotel to Naples with the Circumcised train then on to Florence with the Frecciarossa.

Me too.

If you wish, you can get to Naples by boat, or the Circumvesuviana as you will be boarding at the origination point and going all the way (nearly - just 1 away) to the end, and then just upstairs for the train to Florence.

I'd spend one more day in Sorrento. In my experience, there is always something more to do there.

I wish I were in your shoes - it has been far too long since I was there (4 years).

Has the train had an operation, Roberto?

Like your new handle BTW.