I am concerned about the ZTL....all we want to do is pick up a car from an agency near the train station & get out of Florence with no fines. The following week we would like to return it and take the train back to Rome. We only plan on using car to drive in Tuscany - to and from villa to grocery & local train staion, perhaps to Sienna (and park outside city) and Volterra (again - park outside city). I was told that agencies on the following street in Florence makes it fairly easy to get in/out and avoid the ZTL - please confirm: Via Borgognissanti - Thrify is on that street Our other option is to take a taxi to airport and pick up a car there bu now you have added on two taxi rides and the surcharge for picking a car up at an airport.
It's Borgo Ognissanti. That road is a free corridor out of the ZTL to the west (or northwest whatever it is). Don't make any turns until Rosselli and you're theoritically okay. The glitch is that once you hit Rosselli you also hit a knot of one-way roads that can be a downfall. Make Rosselli your boundry and never get on the city side of it again. Keep worming around and pressing on until you're at the A1 and then go about your business. The other glitch is that you can't get back in the same way due to the one-way streets. My bet is that you'll screw up and will wind up spending more than a surcharge and a couple of taxi fares. I'd also question your premise that the airport is a more expensive location - - you might want to double-check that one since it isn't always true.
I rented car on Via Borgo just for Tuscany trip and I was fine, it's a little stressful getting in and out of Florence but you should be fine
get a really good map and know your routes before you go to avoid the ZTL