Transportation?

Marie, The method I'd probably use.... > Upon arrival at the FCO station, buy tickets both for the Leonardo Express as well as the train to Siena. You can research which trains you might be able to connect with by using the Trenitalia website prior to your trip. > Take the Leonardo Express from FCO to Roma Termini (time 35M, €14 PP, DON'T forget to validate). > Take the next train to Siena. Depending on which train you can connect with, this may be via Freccia to Florence and then Regionale to Siena. It could also be via Regionale Veloce to Chiusi-Chianciano Terme and then Regionale to Siena. When travelling on ANY REGIONALE train, BE SURE to validate prior to boarding the train, or you may face hefty fines which will be collected on the spot! When using Freccia (or other trains with compulsory reservations), you MUST ensure that you ONLY board the train specified on your ticket. If you board the wrong train, again hefty fines. When you arrive in Siena, you'll be at the bottom of the hill and will have to take a Bus or Taxi up to the town. I'd recommend Taxi, as it's not a long trip (and you'll likely be tired and jet lagged). For car rental agencies in Siena, you might check gemut.com or check with a local Travel Agent. Happy travels!

Since you intend to rent a car anyhow and there is four of you traveling together, it is probably more convenient, faster, and cheaper, to rent a car right away upon arrival in Rome and drive to your Tuscan destination. Siena is not served by high speed trains and train fare for 4 people is certainly more expensive than gasoline and tolls for the 250km (150 mi) from Rome to Siena. If you rent in Rome you will be in Siena in 2.5 hours from the time you sign your rental contract. Rome Fiumicino airport has all rental companies you can think of. The drive from Fiumicino airport to Siena is all freeway. If you take the coastal route is even shorter and you save on tolls too. In that case the stretch from Grosseto to Siena is not all freeway, therefore, although shorter, it might take you slightly longer. Either way the drive Couldn't be any easier.

Thanks for the replies. I have been going back and forth on the suggestions. I also wonder if a bus to Siena would be a better option? We are going to be in Serbia for the week before and flying in from Belgrade in the morning. While not a transatlantic flight it will still be about 5 hours of travel time as we have to go through Munich. I only need the car for one week in Tuscany because after that we will be going south to the Naples area to visit family for a week. Not sure about driving a car around? Am I worrying about nothing? I have been to Italy twice but always had family there doing the driving. I am mature and have been driving for over 30 years. Do I face my fear and just do it! Not usually timid about driving anywhere.

The easiest way is to take the Leonardo Express into Rome Termini, and get on a regional train for the 70 minute ride to Orvieto. Hertz' rental location is across the street from the Orvieto train station. The drive up to Siena is very easyabout 1 1/2 hours. The rental car beats having to go on the train up to Florence and double back an hour south to Siena. (The bus is preferable from Florence to Siena anyway.)
Sometimes you can use AutoEurope.com and get less expensive rates than booking the car directly with Hertz. And you still get a Hertz car. I'm a member of Hertz' frequent renter program, and get substantial discounts.

Maybe it's just me, but I would never want to drive a car right after getting off a plane from a transatlantic flight. It wouldn't be safe for me or the other people on the road. I would go with public transportation.

'I would never want to drive a car right after getting off a plane from a transatlantic flight' How do you get home? It's only a couple or three hours up to Siena.

Really, Ed? Okay, how about if I spell out what I thought was clearly implied? "I would never want to drive a new (to me) rental car in a foreign country with signs in a foreign language and different driving rules after getting off a plane from a transatlantic flight." Maybe some people are eager for a three hour drive on strange roads in a strange car after that, but not I.

Marie, make sure that you know what a "ZTL" is and where they are located, if you are even thinking about driving into Siena. (type "ZTL" in to the seach engine in the top of the page) Check auto rental prices, locations,etc., using the Autoeurope.com website. Rent a small wagon, or equivalent. Bring your IDP and and drivers license, your GPS from home, and a Mchelin map of Italy. Contrary to Michael's sage advice, I always drive after my 10 hr flight with no sleep, but it is much easier to take the bus to Sienna. Taking the train to Orvieto, then renting your car, is a good option because you don't have to worry about driving in any traffic during your first foray into Italian roads.