Transportation for 4 days/3 nights around Montepulciano

Comment, in no particular order for your consideration.

If the thought of Italians driving 100mph is distressing to to as it relates to a rental car, you will like it much less if you are on a bike.

getting gas/fuel in Italy is no different than in the US.; its just euros and liters, not $ and gallons.

getting an IDP is about as much hassle as a trip to costco

with all the hills a bike will seem like its UPHILL both ways

with some careful shopping an AT car should not be 2X the cost. (In my case it was actually less)-- you are correct to not want to 're-learn' stick shift in the winding hilly roads of Italy

with all the automated speed enforcement in Italy, some going 100 mph where it is illegal will be as common as some doing 100 mph here

Unless you are proficient motorcycle riders, you do not want to get a motor bike there ( needs an IDP as well)

if your outlook is that driving there is an expensive hassle with nothing but problems, it probably will be, and other transportation options are possibly a better choice.

the mindset is different, but not suicidal, although at a 1st glance that may not be readily apparent.

Enjoy Italy... it really is wonderful

Thanks, Joe. I think we're leaning towards relying on buses and maybe renting bikes for a day. Do you or someone else know if local buses have bike racks? The road going up to Montalcino looks to be the steepest part of the stretch between Montepulciano and Montalcino. Perhaps we could rent bikes in the morning in Montepulciano, put them on the rack and take the bus directly to Montalcino and then spend the rest of the day biking back down to Montepulciano?

The first thing I would do is contact your host and ask about the bus schedules. See if you can even connect the towns you wish to see.
The busses in this area of Tuscany have schedules that are more for the local population. Going to work, school etc. I know you can reach Pienza, but am not sure of return times.

Your choice of picking up a car in Chiusi and dropping in Siena really makes the most sense. I think it could be very frustrating to try to use the bus.

Driving in Italy is no different than driving here. Speed limits are similar.

On the autostrada, 130klph/80mph.
Outside major urban areas, 110klph/68mph
Outside smaller towns 95klph/56mph
Entering small towns, 50/31mph.

If you can't remember these, use my formula. Divide by 2 then add 10%
You'll always be under the speed limit.

As for biking in this area, look at a good topographic map of the area.
Lots of hills. So unless you're very proficient riders don't do it.

I’ll be in Montepulciano in September. For me, driving in Italy isn’t an option I want, so I will be taking the bus over to Pienza. If you’re interested in biking, check out Urban Bikery in Montepulciano on Trip Advisor. They have 82 reviews - 100% are top rating! They rent e-bikes that come with GPS routes to do vineyard wine tastings, etc. The photos will give you an idea of the terrain level. I thought it would be the perfect place to try out the electric bikes for a day on the backroads.

If 77 is the year of your birth, then you are too young to have all those fears of the unknown.
For the Montepulciano area you need a car, like you’d need a car in any rural area in the USA. Try and visit the California wine region in Sonoma and Napa county without a car, then tell us how it went. And Tuscany is even hillier than Napa Valley. You fears of Italians speeding at 100mph are based on fake news spread by Russian hackers on Facebook. The speed limit on the freeway from Rome to Chiusi (near Montepulciano) is 80mph, and there are speed cameras everywhere, so few try to go much faster. Once you exit the freeway, the driving will be on two lane highways full of curves where the speed limit is from 50 to 70 km/h (30 to 45 mph) where going above the speed limit is even hard due to the curves.
If you can drive in the USA, you will be able to drive in Italy. Just do your homework on traffic rules and European road signage, and of course get yourself an IDP, for $25 at AAA.

As an example, I searched the price of a compact, with auto transmission, full zero deductible insurance, with pick up in Rome and drop off in Florence, and it’s less than $350/week. So basically less than $60/day (weekly rates are based on 6 day rentals), including mandatory insurance, which is the bulk of the expense.

Tolls will be minimal for you only for Roma Nord to Chiusi-Chianciano on the A1 freeway (about 80miles), therefore exactly €10.50 ($13).

Fuel costs are higher than in the US (€1.50/liter, therefore a bit over $6 per gal), however cars are fuel efficient and distances are short. I will be surprised if your driving will amount to more than km 500 or 600 in total. So your entire fuel needs will amount to no more than 30lt, or no more than €45 ($55) at the most.

Check rental prices below:
https://www.autoeurope.com/