Chicago-Rome-Florence

Is there a reason you are not flying directly to Florence? Are you just going to Florence? If you give us your itinerary, we may be able to give you more specifics. The train you take from FCO to Termini is the Leonardo Express, cost is 14Euro and it take about 30 minutes. you can buy both this ticket and your ticket to Florence at the airport train station. See the roninrome.com site for info on how to get to the station.
easy day trips would be Siena, San Gimignano and Fiesole

Will be using American Airlines miles to book the flight. Was originally going to fly to Heathrow out of DFW and then connect to Alitalia but realized that AA has a non-stop to Florence from ORD. I'm also now considering just staying in Florence 2-3 nights and then adding another town to spend 2-3 nights in. Will be using train only..no rental car

Jane, I think you meant that AA has a non-stop from ORD to Rome and not Florence. The jumbo jets cannot land at Florence. To answer your question, the easiest way to do this is make your way from your arriving terminal to the train station in front of Terminal 3. At the ticket window, have a piece of paper with the words Aeroporto to Firenze SMN on it and hand it to the agent. They'll know what to do. Your first ticket will be on the Leonardo Express that will take you from the airport to Rome Termini. Fare is 14Euro. At Rome Termini, you will change trains to a very high-speed train from Rome to Florence. The Agent will have included seat reservations on our ticket. Make sure that you have about 20 minutes to change trains. The change can be made in 5-7 minutes but 20 minutes is better. Trains run 2-3 per hour so there are plenty of trains. Journey time is 1hr 35min. Fare is 45Euro. You could go on 119 days out and get non-refundable and non-exchangable fares of 19Euro on the high-speed but this is not advisable unless you leave time to de-plane, clear immigration, retreive your luggage and make your way to the airport train terminal. Plus, have to allow time for the possibility of your plane being late. If your train departs and you are not on it, your ticket is toast. You'll do just fine by walking up to the ticket window and buying your tickets to Florence.

Thanks, Larry! Yes, I did mean to say Rome from Chicago. The train is easy enough..I took the train from Sienna to Florence two years ago and had purchased my ticket at the walk-up machine. Now, I just need to decide what other town I want to stay in after Florence. Tough decision!

Have you considered taking the 150 mile train ride from Florence to Venice? Then catch a flight back to Paris de Gaulle where you can take a direct flight back to Dallas on AA.
If you cannot fly back on "miles" from Venice, the EasyJet flight over to Paris is very, very inexpensive. You'd just have to fly light (1 bag) to keep from having to pay extra for a bag.

Thanks, David...excellent ideas!