The Costa Concordia Northern Mediterranean Cruise, April, 2008
First: This cruise was my 6th. I was on Holland America for Alaska, Princess for 2 Mediterranean cruises, Renaissance for Greece and Turkey (pity it went out of business—it was an awesome cruise line) and Princess for the Panama Canal. All of these cruises were excellent.
If arriving at the Civitavecchia port by train (the express from Rome's Termini takes about 25 minutes and cost 11 Euros each one way), you can easily walk North along the waterfront to the port—it's about 6 blocks. Buses at the entrance to the port will take you to your ship (the buses are labeled). Pulling luggage, it took us only 15 minutes to walk there. Civitavecchia is a small town with limited facilities, so you probably would not want to spend a vacation there. (Train tip, given to us be a local: If the train is crowded, then just sit in the restaurant. By a coffee or glass of wine and you can stay there for the entire trip).
We were on Deck 1, aft. The room was a typical cruise ship room. Limited space, but adequate. The bathroom was actually a bit nicer and larger than any other ship I've been on. The decorating was muted and not displeasing. The service was adequate.