We will be in Siena on a Sunday in September, are any of the shops or sites open. My daughter has my Rick Steves book in Rome right now so it is hard to plan MY trip!
Il Casato Viaggi mentioned in Rick's book has a Sunday afternoon tour on a bus going to San Gimignano at 2 pm for 35 euro with stop at winery and tasting. E-mail is email@example.com. 10% discount with Rick's book
It is a tourist town. Everything will be open except the museum and tour overlooking the plaza.
based on last 12 days in italy much will be closed on sunday....caution is advised.