How much time would this travel distance take & what prices are taxis and train fares?
From FCO take the leonardo express train (14 euros) to the termini station, half an hour. From there you can take the train to civitavecchia (4.50 euros), just over an hour. Once at the train station in Civitavecchia you can either walk, about 15 minutes, or take a cab to the cruise terminals.
Donna
From FCO you can take the FM1 regional train, instead of Leos Express. FM1 from FCO to Roma Trastevere 8.00E, then change platforms to the Civitavecchia train, 4.10E You can buy both tickets from the newspaper stand at the FCO station. Why go all the way to Termini for 14E on Leos Express, then have to walk a long way to the next track for your Civitavecchia train, which stops at Roma Trastevere on it's way to Civitavecchia. You can save 6.00E this way.
My wife and I went the other way when our cruise ended on 11/3/10. We had planned to take the shuttle bus to the port entrance and wheel our luggage to the train station, but decided not to the night before and (fortunately) found another couple similarly situated. Metered taxi fare (van) for the one hour trip (at 7 AM) from the cruise ship dock at Civitavecchia to FCO airport was 183 euros. I tried to negotiate a flat fare when we hired the taxi, but the driver said he was not an independent driver and the taxi company said he had to use the meter. With tip, each couple paid 100 euros, still less than what the cruise ship company was charging for airport transfers by bus. Of course, if everybody departing cruise ships tried to take taxis to FCO, there wouldn't be enough of them.
It's also worth checking sites like the cruisecritic.com site in case someone else on your cruise is getting in at the same time and then sharing a car service. We were able to share a car service ride (we used romecabs.com) with 2 other couples for Civitavecchia to Rome and got the cost down to something like 60-70 euros per couple.
Since Larry posted the question in April, I assume it was a summer cruise and they are home now. Sometimes it is helpful to check the date of the original posting.
Larry, check out Romecabs.com. We used them for a shuttle between Ciampino and FCO. They were wonderful, fairly priced, prompt, and courteous. If you go to their web site, and plug in your data, you will see that they charge one fee for two people, and a little more for four. Check out their reviews on Trip Advisor.