Tuscany itinerary too much?

If you want scenic drives, stay off the main drags.

It will probably take over 2 hours to get to Civita, and that's using the ugly route (A1).

Half an hour to San Gimignano? At least 2 hours on a nice route.

Leave early, Spello and Assisi on the same day. Both worth it.

No experience with any countryside wineries or cheese farms. I'd definitely include Pienza with Montepulciano.

Abbazia di Monte Oliveto Maggiore is a great visit and a good place to eat. On the way, Lucignano is an interesting place. Cortona too, if not in your plans?

You can do Montepulciano and C di B on the same day --- C di B is tiny. We did like visiting it, but not 3-hours-round trip worth. I wonder if you would enjoy Gubbio more --- people live there, good restaurants, and the birdcage lift to the top of the hill is fun. Not heavily touristed, either. An hour and 20 minutes from Castiglion Fiorentino, and, depending on what you want to see or do in Assisi, could be explored on the same day.

Remember that you shouldn't drink and drive in Italy the way people do in America. Also, there are lots of wineries much closer to where you are staying.

San Gimignano was hellishly crowded with tour groups when we did a day trip there in late September 2022. It was hard to see the charm. With a car, you can get to many towns in Tuscany and Umbria that most tourists can't. Like Gubbio. But people here can tell you their own favorite less-visited hill towns.

As for maps --- my family, friends, and colleagues tease me about how I combine my Google Maps with my needing a paper map to scribble on and draw arrows on. But I persist in putting the green flags on my Google map of an area, then printing it up several times so that I can write in town names much larger, circle places, travel times between towns, comments, questions, things to google on, etc.. It helps me think and decide about stuff. I make a clean final copy before we leave home and I do use it while traveling around Italy, even though we use Google Maps for actual navigating while driving.

So smart to do that map prep Nancy! You never know when a road closure or something can happen, and then being familiar with routes and other towns you’ll pass through can save the day. I spend more time on Google Maps planning a trip as I do anything else.
Kathy I know you are exhausted now, but before September do play around with maps a bit, it can make a difference when you need to change things on the fly. I decide what I want to see, then adjust the itinerary so I’m not in the car more than i want to be, but my max may be lower than yours.

hey hey Kathy S
with your short time in tuscany, september is harvest festival season with many town/villages enjoying weekends for "eat drink & be merry"
discoverytuscany.com
calendar of events in tuscany in september (scroll down to months & click september). hope you find some time to attend, they are so much fun. bring small denominations of cash euros. be very careful with wine tasting and driving, very strict unless you have a DD, have no clue about parking and if a taxi available. just keep a number with you. also it's mandatory to have and IDP (aaa.com/IDP) to drive in italy, get it before leaving the states.
we did a few around some towns, my favorite was in bardolino on lake garda (festa dell'uva). check with your host/hostess about wineries and can you visit on your own or need to make reservations?
we would buy the local wine, bread and salami/cheeses at festival and have happy hour at our apartment. it was fabulous.
go have a great time.
aloha

To expand on what Gunderson said above . . . Many of the roads in Tuscany are mostly 2 lanes, narrow, and winding. It can easily take an hour to cover 25 miles.

I consider C d B a monumental waste of time, when you have so little. What about Siena or Pienza?