Hi
I don't know how the
Disney Cruise ship works the tours, but whenever we have cruised on a 'Rome on your Own' they drop you off and pick you up at the same point. Whether this will be the Vatican or not, I don't know.
However, the Vatican could take a day in itself and depending on the queues when you get there.
I would avoid the Vatican Museum, it is a lot to look at and to be honest after an hour or so you do become a bit blase about it!!! Try for the Sistine Chapel, which will be quicker to look at, although you may be queuing for a while to get in, you should allow a couple of hours.
You could get a taxi, or the metro, which only has two lines. I think you will need to change once to get to the Colliseum.
Alternatively, you can walk up past some sites, Rome isn't really very big and you see so much by walking. We did this with our four year old in a stroller.
Got the train ourselves into Rome, getting of at the Vatican, then walked down the main street from St Peters, towards the Castel St Angelo. Go over the bridge acrross the River to the Piazza Navona (used to be used for Chariot Races), a lovely square, lots going on, cafes etc.
From here walked to the Panthenon, have lunch (restaurant on the left (back to Panthenon), does a good all in deal, pizza and beer with olives etc. Then walk through (signposted), to the Trevi Fountain and Spanish Steps.
From here, you could get the underground to the Colliseum, although we walked it! Bit of a road, but past the Forum, which was interesting, to the Colliseum. We then got the metro to the central station to catch a train back to the ship.
Try and do a tour of the Colliseum, it makes much more sense! There are people dressed as Gladiators outside, as a photo opportunity.
But it would depend on what time you have, as you will need to get back to your pick up point.
Rome is great for just wandering, get a good map and walk, there are very small signs that point you in the vague direction of monuments, but it isn't an exact science without a good map! Taxis are good, but can get stuck in traffic, agree your price before you start!
Also think about the hop on hop off bus, you get a ticket and can use it all day, they do a circuit of the main sights with a commentary and you can get off if you want.
Don't be worried about the metro, it is quite safe, as long as you are savvy about pickpockets (who will also unzip backpacks, so beware), I don't think it is any worse than any other large city in the world!.
This site may be useful.
http://www.rome.info/sights/
Enjoy, but don't get too hung up on seeing everything, it just can't be done!
Kate