We would recommend the trip to Pisa. The coach journey was about 25 mins but the walk from the coach drop off point to Pisa itself was about 25 mins. The buildings are spectacular and well worth the price of the trip and long walk. The guide was very informativ.
The trip into Rome is well worth the visit and I would recommend that you take a Taxi to the rail station and get into Rome that way. It's 9 Euros return and the total cost is a lot less the doing it through the reps on board the ship. Hope that this helps you.