Best Tuscan scenery

Does anyone know if it might be more scenic between Pienza and
Montalcino vs. Pienza and Montepulciano?

You are taking about 2 consecutive segments of basically same road- each no more than 15-30 min drive.

I did a 9-day road trip this past summer in Tuscany. The best scenery like you're talking about is between Siena and Pienza/Montepulciano. In the RS Florence/Tuscany guidebook, do the Crete Senesi drive as well as the Heart of Tuscany drive. He even notes in the driving directions where the most famous views are. Be aware that most of the pull-offs are usually very small and sometimes will only fit one car. I missed a few due to other cars already being there and sometimes because they were around a blind curve, and I couldn't see them until it was too late. The drive from Florence down to Volterra/San Gimignano is also lovely, but the views get better the farther south you go. I would do San Gimignano as a day trip from Volterra or possibly Siena. Find a few bases where you want to explore Tuscany by car. I used Volterra, Siena and Montepulciano as my bases, and would do the same again. Each offered a slightly different flavor, and Siena is a much bigger city, so that gave some variety.

Thank you ! What a wonderful trip that must have been!
If we did San Gimignano, we will be doing it with a tour company called "Fun in Tuscany" which would include a vespa ride!

As for Pienza and Montepulciano - how was the drive between the two? Scenic?

Just wanted to say that we did a Vespa tour with Fun in Tuscany in 2018. It included San Gimignano and a great winery experience. Beautiful scenery. Very safe. Guides were so friendly and entertaining. And such a great time at the winery. This was one of our most fun travel experiences. I hope you enjoy your trip.

The drive between Pienza and Montepulciano is not the most scenic part of Tuscany. Part of the drive is blocked by trees/bushes. But it's still very pretty. Just not the "Tuscany postcard" views like Crete Senesi. I would recommend driving up to Monticchiello for great views back at Pienza. The best views of Montepulciano are from SP146 just south of town. I found some place to pull-off and take a few pics.

So good to know that you guys had a great time Kathy - with the Vespa tour. We were on fence about it but just booked it today!!

I will be sure to include Monticchiello route then to get that scenic view
So what is the Val d’Orcia scenic drive? I thought that connected Montepulciano and Pienza

RS refers to the drive between Pienza and Montepulciano (and other towns) as both the Val d'Orcia Loop or the Heart of Tuscany Drive. They're the same. I also highly recommend Bagno Vignoni and the Rocca d'Orcia.

Google "SR222 Tuscany", you'll come up with info like this...

https://www.ultimatedrives.net/top-10-roads/details.php?route_ID=60073

We prefer the scenery in Chianti over the area around Montepulciano as it is much greener while the other area is more yellow/ at least when we have visited.

Bill is correct about driving from Siena on the Sienese Crest Road to Montalcino that'is incredibly scenic with rolling hills and many different landscapes with postcard views. Don’t bother getting an early start because this windy road can be foggy in the morning but I did this in Nov which may have been why.
I also liked the drive up to San Gimignano as you get closer to it. The drive between San Gimignano and Voltera is more forestry but still very attractive with it’s bright green grass and trees offering another scenic landscape view.