Our plane will arrive from the US at 7:45 am at the Rome Airport. The cruise shuttle will take us to the port at Civitavecchia at 4 PM. The Hilton will let us check our bags. What can we do during those 8 hours? Sitting around in the Hospitality Lounge at the Hilton sounds quite gruelling. Should we consider going into Rome by train or taxi to a seaside resort? I wonder if we will have any energy to explore Rome on foot being exhausted and jet lagged. Any suggestions will be appreciated.

YEs, it depends on how you arrive in ROme after many hours on a plane. The possibilities are many, but I would suggest either to go to Ostia, which is a seaside resort and have lunch in a restaurant facing the beach, visit OStia antica or Ostia (modern town), or yes, take the Leonardo Express which will take you in half an hour to Termini and from there either take the bus #64 that goes to Piazza Venezia (visit the Vittoriano and Clousseum) or get off at the stop near Sant'Andrea della Valle which is within walking distance from Piazza Navona and just stay there, enjoying the beautiful view, have lunch in one of the restaurants of the area, walk in the narrow streets around the Piazza, arrive up to the Pantheon and then take a taxi and go back to Termini to take the train.
If you prefer to go by taxi, consider there is also the so called limo service, (lots of good reviews here in this forum by many fodorites) which will drive you easily to your destination in Rome. This second option is IMO more relaxed considering you wont be that fresh after getting off the plane.
Exploring Rome on foot is not advisable, I would just choose a place you WANT to see in Rome (I suggested Piazza Navona because it is one of my fave places in Rome, but you can choose another place).

Head for Rome. Take a cab or shuttle service and have them drop you in the historic center--also arrange a pickup location and time. Stroll, sit in cafes, visit the Pantheon, have a nice lunch, head back to Civitavecchia. Resist your impulse to nap--stay awake, but take it slowly.

Hi richard,

You want to keep moving, even albeit slowly. Try this

From the airport take the train to Roma TE.

Purchase a ticket from the tobacconist upstairs before getting on the tube.

Take Metro Line A direction Battistini to the Barberini Metro stop (2nd stop). From Pza Barberini go West on Via Tritone abt 1 km to Via Stamperia on left. Take Via Stamperia to the Trevi Fountain.

Ristorante Scanderberg in Piazza Scanderberg, 1 blk to the East of the Trevi Fountain and across from the pasta museum. It's a tiny hole in the wall that you can easily miss if you're not paying attention.

Then head west on Via della Muratte which will cross Via del Corso, change names (Pietra, Pastini) and, a short distance later, lead you into the Piazza della Rotonda (on left) and the Pantheon (abt 3/ 4 km).

Return to Barberini Metro stop and take Line A dir Anagnina back to Termini.

You can, if you wish, walk up the Via Veneto to the Spagna metro stop and take the metro back to the train station from there.

A strong second vote for Ostia Antiqua - a 5 minute cab ride from the Airport.

http://travel.waltpohl.org/ostia_antiqua.html