Easy walk to the main port area and safe as well even late at night. Easy walk to many excellent port restaurants and a short trip by taxi or bus to the many beaches well worth visiting. Likewise to the main shopping area downtown. All manageable within a one day stop-over.
The port of Rome, Civitavecchia, leaves much to be desired other than serving as a port city and offering some quality accommodation for reasonable prices and restaurants close to the debarkation area of the port. Otherwise not a recommended destination!