We would like to take a countryside tour to the port the day before our cruise leaves, any ideas?
It could be done by train...there is the express train that goes directly from Leonardo de Vinci to the centeral terminal in Rome (11 euros, about 30 minutes on the train). From the central train terminal (Termini), Civitavecchia is another 40 or so minutes. I doubt this ticket is more than 10 euros. I'm not sure if it is the best way, but its one option
Here's a similar post:
Rome to Civitavecchia