Best day trips from Florence

robyn,

In addition to Siena, some other popular locations for day trips include Lucca, Padova or Pisa.

Your statement about "places to drive to and then return to Florence at night" raised a few red flags. A few questions.....

• Have you driven in Italy before?
• Are you aware that each driver will require the compulsory International Driver's Permit, which is used in conjunction with your home D.L. The IDP's are easily available for a small fee at any AAA / CAA office for a small fee, and are valid for one year.
• Have you researched the ZTL (limited traffic) areas that exist in many Italian towns? Hefty fines for each pass through them, which you won't be aware of until several months after you return home, when unexpected charges start to appear on your credit card! Florence is especially risky to drive in as the city is just about saturated with automated ZTL cameras.

If you're planning to visit any of the Tuscan hill towns that are not well covered by public transit, then a car is useful. The Cinque Terre is best explored by train as there's limited parking in most of the towns (Monterosso has the best parking options). For the places I listed above, travel by train will be far easier (and probably far cheaper in the long run).

Fiesole and Pisa/Lucca. Personally, I wouldn't be driving - I'd be taking trains or buses - usually very convenient in Italy except for more rural areas.

Because it won't take a whole day to get from Cinque Terre to Florence, you might arrive at your hotel before you can check in. We decided to stop in Pisa on the way to Florence. We had plenty of time to tour and have lunch and make it to our hotel at just the right time to check in.