Hi, as said by others Rome is easy, and cheap, to get by train. Tip for the Colosseum, book ahead or grab on of the "authorised" personal tour guides outside, it costs 22euros, but you go in ahead of the queue and then drop the guide and go around on your own.
The cheapest way to get to Rome from Civitavecchia is by train. If you do a search on Rome on this site you will find information about this from other contributors. With the 'Rome Alone' excursion you are dropped off at the Vatican which allows you to get in there early before the queues get too long. Remember to respect the dress code - long trousers for men and covered shoulders for women. You can easily walk from the Vatican to the Coliseum and see lots of other things on the way. Rome is very easy to get around on foot and the city buses are useful when you get a little foot weary. For our first time in Rome we got a city map and planned our day. Just make sure you leave enough time to get back to the coach or to the ship. I am sure you will love it. Enjoy.
Unless you go on an organised trip, you would have to queue for at least an hour at most times to get into St Peter's. So if you want to go inside and see the Pieta I would take a trip. Seeing Rome by yourself can be done by using a hop on-off tour bus and you can usually get into the Coleseum fairly easily by doing this.
On the Rome on your own excursion with MSC, the coach dropped us off at a multi storey car/coach park which was right beside St Peter's square (at the back). there seemed to be lots of other coach companies dropping off cruise passengers here too, so this may be what Costa also does. We were there on a Sunday and were dropped off in time to join the service. The hop on hop off bus stop was just around the front. You can't buy the tickets onboard you need to get them from the tobacconists kiosk directly opposite the bus stops. You will have plenty of time to do the loop and get off at some but not all stops. we didn't go inside the Vatican because there was such a long queue and it was so hot - just couldn't face a 1-2 hour wait in 35 degrees. Soif you definitely want to go inside you may be better to do an escorted tou.
Hi Moira. I tend to agree with both of the previous writers. Rome is very tiring and the queues for the Vatican enormous. An organised tour is the best way to do it. Once you have become more experienced doing the rest of Rome is best done on your own and it is walkable if you plan your routes well. Buses are useful and so is the metro but do watch out for the thieves particularly on the buses from Piazza Venezia to St Peter's. You can also arrange a Vatican tour through various net sites which get you in early and give better viewings, but this time I would do the ship's tour and go back again. Regards ....Nei.