9 Nights in Tuscany (First time to Italy)

I prefer to pick central locations as base, and take day trips from there, because checking in/out of hotels, packing/repacking, are all time consuming activities. In particular all the locations you are visiting are within 60 to 90 min from one another, therefore very easy to do on day trips from a central location. For example by the time you pack, check out of one hotel, check in in another hotel, unpack again, I've already driven from Siena to Volterra and back (and that is the longest segment in your itinerary).

Regarding driving or using public transportation, that is up to you. Generally small villages like Montalcino and also Volterra are easier to reach by car, because buses have infrequent service to those small towns (and no service on Sunday). Big cities/towns like Florence, Siena, Pisa, Lucca, Arezzo, Pistoia, are all easy by train or bus (Siena is easier by bus from Florence).

My suggestion is:
If you use public transportation you could base yourself in Florence for the entire trip. Florence is the transportation hub of Tuscany. Or at most you could split your stay into 2 locations only: Florence (5-6 nights) and Siena (3-4 nights), which would be your 2 bases (Florence needs 3 nights just for the city itself). Siena is a good base for Siena itself, the Val D'Orcia (Montalcino). Florence is best for everywhere else.
If you fly in/out of Florence, go to Siena first upon arrival, then return to Florence for the last 5 or 6 nights before flying to AMS.

If you rent a car and drive, find a small village or country villa anywhere between Florence and Siena. Avoid staying in either city with a car, both have severe traffic restrictions for non residents' cars. When you visit those cities by car, coming from the countryside, you need to park at a lot outside the historical city center (cars are not permitted inside the city centers).

Of the places you mentioned, Volterra will be the only tricky one for a day-trip. This website gives links to bus schedules.

It's nearly always possible to reach a place of tourist interest in Italy by some form(s) of public transportation, but it's true that the schedules may be such that you spend nearly a full day visiting a place that would require only half a day by car. I always stop at the tourist office of my base city to inquire about transportation options to the more difficult towns so I'm sure I at least know about all the options. Then I check the precise timing at the bus station. If there's an English-speaking information counter at the bus station, that is the best of all.

It's worth considering a one-day bus tour that hits several small towns of interest to you. A lot of the tours from Florence go to larger places like Siena, Pisa and Lucca, which you can easily visit yourself, so you're paying quite a lot extra for the convenience of not having to buy your own bus or train tickets, and there's the disadvantage of having to leave when the tour bus does. On the other hand, for visiting three or more smaller towns in a day, which is difficult if not impossible to do on your own, a bus tour may be worth the cost and the loss of flexibility.

Day-tour options will be greater if you are traveling during peak season. Definitely check schedules ahead of time if you think you might be interested, because some tours may run only one day a week. You can Google to identify options, but also check the Viator website. Viator sells tours run by many different companies and may turn up additional possibilities. (If you want to book directly with the operator--which I suspect might save money--you'll have to do some further Googling.) Check tour reviews before buying.

I too am a solo traveler leaving next April for Italy, 11 nights. Already I regret including 3 nights in Rome. Not that I don't want to see Rome but wish I had given myself those nights in my other locations so I could fully enjoy the sights without feeling rushed. And there is so much to see in Rome, 3 nights isn't close to enough time. I have three nights in Florence but really only two full days. I wish I planned another day. I picked where I wanted to go, which hotel to stay in and the things I wanted to see. I booked hotels before I thoroughly investigated what I wanted to see, when they opened and for how long for example. I feel like I'm getting an appetizer instead of the full meal. For what it's worth I'd look at all your locations and really research the sights in each location you want to see. This might help flesh out your itinerary.

Not enough time in Florence
Too much moving around, choose which towns you want to see the most (2 ideal / 3 max for 8 nights) and stay there and do a few day trips to see the others. For example there is little reason to stay over in both Volterra and Siena ; choose one and day trip to the other from that place.
None of the areas you are talking about are very far from each other.
Make sure to see the town you are staying in, in your plan you only have 1 full day in Siena and plan on day tripping that day to Montalcino which will take all day and unless you have a car is probably not a simple day trip.
Pisa is a good half day trip, not sure why you would spend the night in your schedule.
Not sure time of year but even if summer probably in your case makes the most sense to choose between Pisa or a coastal town not both.

Your posts says 9 nights in Tuscany but you really only have 8, since Day 9 you are traveling to Amsterdam.

Firenze and Siena are the classic base cities for Tuscany. You could daytrip to Montalcino and to Volterra without packing up and changing hotels every two days.

If you give 5 nights (count nights, not days) to Firenze (and daytrip to Volterra and to Lucca/Pisa on different days), you would have two nights in Siena, which could include one daytrip to Montalcino. Or 4 nights in Firenze and daytrip to Volterra from Siena, adding a 3rd night there (distance by bus is about the same to Volterra from either Firenze or Siena).

Wow! Thank you for the help! Looks like I need to choose a "base camp" and then decide what day trips to take. More research to follow.

Thanks again!

Florence is the better choice for a day camp. You can easily visit Siena from there on a day trip as well.

However if you want to visit the area of Val D'Orcia (Montalcino, Montepulciano, Pienza, for example) you need to base yourself in Siena for a couple of nights or three, because those villages are too far from Florence if you don't have a car and rely on buses.

All other towns you mentioned and more, should be visited from Florence, therefore you should base yourself for most of your stay. Volterra is equidistant from the two cities, but Florence gives you the extra option of taking a fast regionale train to Pontedera (between Florence and Pisa), then the bus from Pontedera station to Volterra. I think that option is the one that provides the most bus links and is faster (also a bit less curvy, therefore less chance of puking on the bus).

We spent 8 days in Tuscany last December. We went everywhere you mentioned except Pisa that got left off the list because of time restraints.

We stayed in Greve, which is centrally located (20 km south of Florence) and did day trips. I hope our experience will help you have a great trip.

1) Drive or use public transportation? We did a little of both. There's a ton of back road scenery that hard or darn near impossible to see using public transportation. We enjoyed the freedom of exploring on our own time schedule. If you are a careful driver, you'll do fine. Driving in Tuscany is not much different than driving in the US. Obey the speed limits. Learn the signage before you go (it's not that hard). Take a Garmin with an SD card of Italy. I spent an hour at home before we left entering and saving every address, including parking lots, that we planned to go to. By the end of the trip, I knew the region so well that I didn't have to rely on it to get around. I think the dreaded ZTL problem is overblown. The zones are well marked and you have to not be paying attention to make a mistake (although I almost did in Siena).

The one time we took public transportation was from Greve to Florence. Buses run every 10 minutes or so since many live in the country and commute into Florence. We were the only non-natives on the bus and had a great time! It's only 4 euro each way. You can catch the 6:45 bus from Greve and be in the heart of Florence by a little after 8:00.

2) Florence - Give yourself 2 days to visit. I wouldn't recommend it as a base because you'll chew up a lot of time getting in and out of the city. We only gave ourselves one day in Florence. I regret we didn't spend at least two. We used Walks of Italy to do a morning walking tour that included spending an hour at the Academie to see David and other works of Michelangelo. We also visited the Duomo We then did the afternoon tour of the Uffizi. They provide your entrance tickets and you skip the lines. I wish we had spent another day to visit some of the other museums and churches. It would be worth the expense to have rented a room in town and stayed overnight.

3) Volterra and San Gimignano - We did both in a long day trip. We spent the morning at San Gimignano, had lunch then drove to Volterra. Both have large parking lots outside the towns and you can leisurely walk from one end to the other in an hour or so. Make Volterra your afternoon trip. Walk just outside the city walls and watch the spectacular sunset, then have a nice dinner before driving back.

4) Siena - You can do Siena in a long day, but two would be better. It's not as jam packed with museums and sites as Florence, but you could easily fill two days at a more relaxed pace.

5) Pisa and Lucca - We had them on our itinerary, but decided we would be too pushed to fit them in. We had been to Pisa before and there's not much more than the tower and baptistery. Instead we took a day to ramble south from Greve, stopping at the charming small town of Radda and ending the day at the Abbey of Monte Oliveto Maggiore. The abbey was a highlight of the trip. The evening vespers are in Gregorian Chant. Besides a lady from a nearby town, we were the only ones there other than the monks. It's a gorgeous, calming service in a spectacular church. It's also close to Montalchino and Montepulchiano. You could do Radda in the morning, catch Montalchino for lunch and the afternoon, then drive down to the abbey in time for the vespers at 7:00 (check the time).

6) Final notes. We scheduled in a down day the first full day we were there. We stayed at Castillo di Verrazano so we had a leisurely breakfast, then took the wine tour, followed by a wine and food pairing that took three hours! The owner kept bringing over samples of new vintages for us to taste and provide feedback.

We spent three days in Amsterdam in July and had a great time! Have fun!

I find the most stressful days as a solo traveler are when I'm changing cities, so I reduce the number of times I do that as it can use up all or a large portion of the day. I love Florence so I have yet to find time for a day trip, but one of these times I will. The nice thing about day trips is you can cancel them! Traveling solo, I have yet to rent a car as I believe driving AND navigating in a foreign country would not be enjoyable, where as public transportation is relaxing. If you are not used to traveling solo in a foreign country, don't run around so much. Relax and enjoy your freedom! Wray

If you decide to go the "base & day-trip" route (which I recommend 100%), I would also recommend an apartment versus a hotel. You should be able to find an apartment in the center of Florence for about the same price as a nicer (but not luxury) hotel room. It will give you more space to spread out and most of them have cloths washers (and maybe a dryer) enabling you to pack lighter.

I easily did Pisa and Lucca, in that order, as a day trip from Florence. It seemed to me that Pisa's main attraction is Piazza del Duomo and the leaning tower. Get there as early as you can to avoid (as much as possible) the hoards of selfie-stick wielding crazies.

I actually preferred Lucca to Pisa. A lot more! Unless you really must see the leaning tower, I would skip Pisa and just go to Lucca.

One way to see the Tuscan countryside is to book a wine and food tour. Walkabout Florence has a really good one. Several wine tastings while letting someone else do all the driving. Just book a small-group tour versus a big-coach tour.

If you are still entertaining the idea of renting a car, read up on ZTLs and Italy's notorious traffic cameras. Also remember that your personal car insurance and most(?) credit card insurance coverages won't cover you in Italy. You can either go with the rental company's outrageously expensive insurance or get coverage through a trip insurance firm. Personally, I would never drive in Italy without extra coverage... You'll also need an International Drivers Permit (available at any AAA office).