In the middle of our Italy trip this July we will be staying for 8 nights in Montepulciano. We hope to use that as our base for exploring several hill towns. We have 9 towns on our list including: San Gimignano, Volterra, Orvieto, Cortona, Montalcino, Pienza, Pitigliano-Grosetto, Civeta di Bagnoregio, and Arezzo. Are there any other must see towns that we should add. Not sure how many to attempt in the 8-9 days we have.
I assume you'll have a car.
Assisi, for sure, though I don't define anything as a must-see. It's all about the time you have and your interests.
I've wanted to go to Gubbio but have never made it.
Siena and close by in Umbria , Assisi.
Siena
Monteriggioni
Lucignano
to name a few.
But there are scores all within 1.5 hours.
https://www.borghiditoscana.net/en/category/villages-en/
https://www.ilturista.info/ch/borghi_castelli/toscana/
http://borghipiubelliditalia.it/toscana/