traveling from Firenze to Civitavecchia (Cruise Port).

It appears to be your best and quickest way. On Trenitalia it's showing between 3-4 hour trip depending on the time of day. You'll connect in Roma Termini station. High Speed train from Florence to Rome, then the train to the port. It's an easy connection. The quickest shows 3 hr 5 min.

Driving shows 168 miles and 3 hours 2 min. About the same as the quickest train but if you hit traffic it'll be slower. You'll also need to drop off a rental car someplace and allow time for that. You can hire a private taxi driver but that is more expensive then the train.

We drove from Monterosso al Mare to Civitavecchia going down the coast and it took about 4 hours at a leisurely pace. From Florence it is about 140 miles if you use the autostrada through Rome. If you go to the coast (Lucca, Cecina, Grosseto) it is a little over 200 miles, some on autostrade. It was a nice drive and we had lunch on the way. If you can drop the car in Civitavecchia you might consider it.

Train is pretty easy. For some people, "best" would be chauffeured limousine.

The quickest is 2:36 if you take one of the few Frecciabianca trains running from Roma Termini to Civitavecchia. Note that a Frecciabianca costs 16 € per person. It's 5 € on a Regionale.

Thank you all. This is helpful