Siena Car Rental Problem with pickup time

Rent your car at the Rome airport and drive from there.

John,
Train to Florence and go to the airport to rent a car.

Hertz has offices near the Florence SNM train station.

I agree with Doug. Assuming that you're flying into FCO, why spend 14 euros each and a half hour getting to Termini, then another 45 euros per person (2nd class) for the fast train and another 90 minutes to Florence to pick up a car you can get in Rome? Once you get the car you will drive another 90 minutes to Siena (depending where you're going exactly). In the same amount of time (or less) and no extra cost you could pick up the car in Rome and drive to your rental. Your won't be driving through Rome if you pick up at the airport, so there are no ZTLs to worry about.

I considered renting a car in Rome but had two issues:
I though we would be too tired to make a 3 hour drive and some of the group have luggage issues. Assuming the luggage can be worked out is it an easy drive?

How many people are traveling and how many bags do you have? The drive will mostly be on the A1 (go to google maps or viamichelin to route your drive). If you're too tired for a 3 hour drive you would likely be too tired to travel to Florence and then drive another hour and half. You'd also still have the luggage issues... Your other option would be to see if you can arrange a car to take you all from the train station in Siena to your rental and then back to get the car the next day, but then you don't have a car that day for important things like food, although I suppose you could arrange for the driver to take you. No idea how much that would cost, though you'll save on a day's car rental...

We decided the the best advice was to travel light and rent the cars in Rome. Thanks everyone.

Great decision. Enjoy your trip.