We are staying in Florence and will do a day trip to Lucca and a day trip to Sienna and hopefully San G. It will be a Sunday and Monday near the end of Sept. Is one day better than another in either place? Or does it really matter?
Look at the museum openongs/closingss dates in Florence bedore you decide. Siena is beautiful. Be prepared the crowds at San Gimi.
San Gimignano is best visited about 4:00 p.m.--after all the buses are gone. And Sienna is at its best after dark--magical. Viator.com often has a organized tour with both cities.