Rome on your own- a bit expensive since you were just getting transport, but the best way to do it if there are specific things you want to see. Overall as a port- great choice, cant really go wrong. Plenty to see/do. Only problem is port is at least an hours drive away so cuts into your sightseeing time quite a bit.
Walking tour around Florence with time to explore on own. Good way to get your bearings and see some of the highlights. Florence itself has plenty to see and can easily put a day in there (more if you like history). Only problem is the distance to port- we docked in La Spezia which was about 90mins-2hrs away. (La Spezia also worth a look). Most boats however dock in Livorno which is a bit closer