For those who want to visit the native town of Napoleon we recommend just to walk around or to book a citytour with one of the locals. If you like French cuisine there are plenty of small "brasseries" where you can taste local and regional food and dishes. For those who likes nature (Corsica is a beautiful rough island) it is better to book one of the scenery excursions organised by RCI
Compared to Palermo/Sicily we visited last year Cagliari was a little bit disappointing. Apart from the cathedral (a must) and a few beautiful avenues there is not so much to see if you are not a real history freek. We missed the warm italian atmosphere that we felt in so many other Italian cities. Cagliari is a nice stop but not unforgettable.
We visited Rome at several occasions (apart from cruises) and each time we are delighted and even surprised by the many highlights of the Italian Capital. This time we just walked around in Civitavecchia and we liked it; there is an old part and a newer one, the harbour is quite big and the people are very friendly. We got a real good italian coffee in a small cafetaria, had a nice chat with some of the local customers and were surprised afterwards that we spent more than 3 hours in that small city. But, let us be clear, if you have never been in Rome you should not waste your time in Civitavecchia.