Staying in Siena for three nights and looking for a hill town to visit. Traveling by train or bus. Looking for suggestions. I have previously visited Montepulciano and Orvieto.
I like to combine Arezzo and Sansepolcro, both reachable by train or bus. You can get to Assisi as well, if you haven't been there already. One of my favorites is Todi (took the bus).
We used Siena as a base for seeing Monteriggioni (old walled city with terrific ramparts!) and Volterra. Very nice 6 hours-or-so including lunch. You coudl tack on San Gimignano for a longer day.