Alghero (sardinia) has nice beaches within walking distance and the old town near the tender dock is great for food and drinks and ice creams. Beware that there may be a queue for the tenders back and it wont be in the shade.
To get to Rome from Civitavecchia we caught the train which was â‚¬12 return and took 50 mins - and it was faultless. On time, clean and with power - incredible job. We walked from the train station to the Colosseum and then got a cab to the Trevi fountains and eventually walked back to the train station. Hot work but good exercise after all the ship food!
Livorno has a lovely beach if you walk to it - again you have to pay to get off the ship but grab a Buss 1R from the main square where the shuttle drops you and its 5 minutes to the beaches - which â‚¬5 to enter. They are all used by locals and not a stripy towel in sight! Perfect beach for kids swimming - safe, clean and warm.
Cannes we went again to a private beach which had lovely loungers, a nice restaurant etc etc. Well worth the â‚¬13 for the day and the kids had a great area to play and rest in the shade. The public beach has no shade and you will have to rent a very expensive umbrella for your 0.5 sq ft of space in the sand.
Barcelona - see above - we went first thing and explored Las Ramblas and the Catedral (not the Gaudi) before all the locals had woken and the tourists had arrived. The local market on Las Ramblas was well worth a visit. Stunning sights and smells.
Gibraltar was ok - its basically a stop to buy cheap booze (Â£6.75 for a litre of Famous Grouse of Â£10 for a litre of 47% Bombay Sapphire ) but we also visited the WW2 tunnels which for Â£8 was a very interesting way to spend an hour and learn of their pivotal role during the war. We caught the bus from the town centre which was much cheaper than the organised tours or the taxi touts.