For Florence etc. The tours office will sell a combined Florence & Pisa trip, but it really is a lot to take in one day. but as you are travelling a long way for this cruise, you may feel it is worth the effort, just make sure you are ready for it. Livorno itelf is an interesting town to wander around, but you will probably be back on the ship within a couple of hours, so we would definitely recommend Pisa, Lucca, or Florence.
For Naples we booked a private tour of Pompeii Sorrento and Amalfi coast from sorrentosilverstar was very good
Hope you have a fantastic & memorable cruise,