venice was very nice, very walkable, take the peoplemover (monorail) to get to the nearest plaza. you need euros (dollars), press the screen to start the ticket process. take the number 1 vaporetto to get to st marks . ravenna was the next port, take the ship shuttle downtown, then you can walk to all the sights in town.
we actually docked in catania south of taormina. we had a private tour to siracusa which was excellent but it poured that day so we had to curtail it. did not go to downtown catania. many people went to taormina so see mt etna but it was covered by clouds because of the rain. need to go back in good weather but many excursions can be taken from these ports. the tour company was very good and i would recommend them, they procured the local guide who was excellent as well
the first day, we did a private tour with romeinlimo(see tripadvisor) very good tour, all day, drivers very nice, flexible, took us to sorrento, positano and then a vineyard. amalfi coast is beautiful, tour was half the price of the ships, we had 3 vans, 24 people
second day, we just walked thru naples, no problem with safety, nice sites, walked the main shopping street to the archaeological museum, about a 30 minute walk from ship
we used shareashoreexcursion in italy for a group transfer to central rome where the driver dropped us off at each of our hotels. used cruisecritic messageboards to form the group, otherwise it is pricey to get from the port to rome or the airport because it is not close. spent the day in rome seeing the major sites, we stayed near the spanish steps at the principessa isabella , part of the clarion hotel chain, nice place to stay, good location