12 day Italy trip

Not sure why you’ve chosen to post under the Italy Reviews section.

For answers to your questions go to the Italy section in countries category and repost.

Only two hours for Siena? Not enough.
You can do San Gimignano in that amount of time. No tour guides needed for either. Assume you will have a guide book.

The “Italy Reviews” section is for your post trip review of lodging, restaurants, tours. If you post this over in “Italy,” more responses are likely. That is the forum for asking questions.

“During the drive we will stop in San Gimignano and Siena, 2 hours each.”

If that’s the maximum time you can allow, I would plan on an hour at San Gimignano and three hours at Siena. If you haven’t been to Italy previously, plan on everything taking more time, i.e. stopping for a sit down lunch is easily an hour. You don’t need guides for those towns. The top sites for Siena are listed in the RS guide book. San Gimignano is tiny, and you can just walk through it and enjoy the views, also. (My favorite ceramic pitcher is from SG!)

What you need, and it is must have, is the Michelin Green Guide.

Google estimates 3.5 hours driving time, without traffic. Google estimates are often unrealistically low. Take into account that you can't drive into the historic centers, so you'll also need time to find parking and then make your way to the sights.