Tuscany is the ideal territory for day trips from Florence. Trains and buses connect the main towns efficiently, and the landscape between them — cypress avenues, olive groves, vine-covered hills — rewards a slower journey by car or even bicycle.
Siena (1.5 hours by bus or train) is the most compelling day trip — a medieval city frozen in time since the 14th century, with the Campo as one of the great urban spaces in Europe and a civic museum containing Sienese painting at its peak. Go by bus via the Chiana valley for views.
Pisa (1 hour by train) is underrated beyond the Leaning Tower. The Campo dei Miracoli — cathedral, baptistery, tower, and cemetery together — is a genuinely extraordinary ensemble.
San Gimignano (1.5 hours by bus) has its medieval towers intact, tremendous Vernaccia white wine, and the extraordinary Collegiata church. Worth a half-day.
The Chianti wine road south toward Siena is the classic Tuscan drive — book a car and spend a day at cantinas in Greve or Radda. Fiesole, 20 minutes by bus above Florence, has Etruscan and Roman remains and fine views back over the city.