Lets take the stops that I have been to and give you some advice.
Rome- take shore excursion or private tour and see the Vatican and the Colisium. These are musts
Florence/Pisa- again shore excursion or private tour to downtown Florence, they have the academia of art, this is where the orginal statue of David is, and there are a lot of other paintings and stuff. Downtown Florence has great shopping. Pisa has the leaning tower and thats about it
Dubrovnik-the walled city. RCI should have buses by the dock to take you to and from the walled city. Check with shore excursion desk for the bus times. The walled city is a gem and must see
CorFu-I took Achillean Palace and Greek Monestary tour. Palace was ok, monestary was cool. RCI has buses to take you downtown Corfu and back. Again check with shore excursion desk. I have been to Nice and not Caanes. Hope this helps.
Freedom of the Seas Dec 11
Allure of the Seas: Jan 11
Voyager of the Seas: May 09
Splendour of the Seas: May 07
Explorer of the Seas: Jan 04
Majesty of the Seas Jan 99