Planning Pisa to Venice Sept and/or Oct and/or Nov

It looks wonderful. Time of year would affect whether or not CT would be feasible - I'll leave that to be addressed by those who have been.

• Lucca can be seen comfortably in half day. Do you need 3 nights there? I guess one could take the Lucca to Aulla scenic railway or visit the Garfagnana valley and Barga. Actually it wouldn't be a bad idea to take the Lucca-Aulla railway to the Cinque Terre. Takes a bit longer, but it's worth it.
• four nights in Siena are enough to squeeze more day trips than just San Gimignano. Everything important to see in Siena can be seen in less than a day. The rest of your time you can devote to a bunch of nearby towns.
• Do you need to split your stay between Ferrara and Ravenna? Hardly! The two are close enough (just over 1hr by train) that you can visit both from one location and save yourself a time consuming hotel switch. Actually in your shoes I would stay the whole 4 nights in nearby Bologna, the most important rail hub in Italy and the capital of Emilia, and visit everything from there, maybe even pretty Parma, if you have the time.

Thanks Roberto for your insight. Looking to add Castelnuovo de Garfagnana Thursday market to our time in and about Lucca.
Your suggestion about combining Ferrara and Ravenna makes a lot of sense, and I will look into using Bologna as a base, although small town vs. city is a consideration our group will have to make. Will look into seeing other hill towns from Siena. Our hope of spending extra days in small towns was to get a "feel" for the town, rather than rushing through areas.

Lucca is a wonderful place to just be - three nights sounds great to me, particularly since you'll be working off the jet lag.

Roberto always has an efficient travel plan, sometimes a little fast-paced for me; I love spending a few nights in a small town. But I agree that you could choose Ferrara or Ravenna as a base for the other. Padova would be nearby as well. Bologna doesn't feel like a big city if you stay in the Centro Storico.

Zoe is right. My travel style doesn't fit everybody because I'm restless by nature and I'm the type who gets bored quickly. I don't believe that Rome or Paris deserve more than a couple of days each and I can easily visit 5 to 7 Tuscan towns in a day. If I were your tour guide you'd be so exhausted that you'd think a marathon is a walk in the park. But my restless nature makes me very efficient at squeezing a lot of stuff in a day, and I think you can squeeze much more if you base yourself in Bologna. Bologna is not a small town, it's larger than Florence in fact. Nevertheless the historical center is compact and largely car free. You will feel like in a smaller town.

Keep in mind that the more you try to do in a day, the greater the possibility that a mistake or obstacle can derail your plans. Even if you can visit several smaller towns in one day, not difficult to do with a car, you may want to plan a catch-up day in case you need it; if you don't need it, you will find plenty of things to do that day.

I would go around mid-to late September into the first week of October.

And I don't like the heat and the crowds, so I'd go as late in the year as possible - maybe save some money on off-season rates for air and rooms.

I stayed in Bologna and day-tripped. Loved Bologna. My hotel was about 1/2 way between the train station and the center, maybe 10 minutes' walk to each. Ferrara's old center is farther from the train station, so it's okay for a day trip, not as good as a base. On my first visit to Ravenna, I stayed 2 nights, lovely little town.