If you get the chance to go to Florence, take it; it is wonderful. Rome is a must, although there are different excusions to Rome, we done the Vatican and the coach drove around so you could see the Colleseum, etc. Etna and Toarmina if you go to Sicily are also outstanding.The guides you are given are excellent.
Do euo camp dont know about rest its about 2.25 for pint of lager and soft drinks are 1.40 we used to go to shop when we got into port and bought juice kept in cabin put in ice bucket kept it chilled drinks quite cheap its only soft drinks we used to buy water ashore as well you get one in cabian its about 2.15 for 1.5 bottle we buy first one then buy rest a shore enjoy your cruise we allways do.
Explore Genoa alone it has an amazing harbour area, and you must explore the narrow streets, piazza de ferrari, plazzo Ducale and the Catherdral. Walk the Aquarium on the quayside and then just cross the road from there and entering into the narrow streets its amazing and you cant get lost. Also the Full Day Monaco and Monte Carlo trip was amazing for views of the Cote D'Azure and exploring the amazing monaco with plenty of free time too. As for Barcelona I've been there before and it's quite a large city so I would advise a trip if you were wanting to see such sights as the Sagrada Famillia (catherdral) etc.....Hope that helps.! p.s. it's £1.45 for coke.