Itinerary all set for Milan to Venice to CT.
After CT have 8 nights before leaving for home.
Plan to go to Florence then Rome but would like some time in the Tuscany hill towns. Is this reasonable?
Is it best to go for day trips from Florence to Tuscany or stay at a town and go from there? Would have either 2 or 3 nights.
Not eager to drive but would consider if that would give us more time to explore.
Most interested in seeing the countryside, eating good food, maybe a cooking class, walks/hikes.
Driving through the Tuscany hill town area will give you the flexibility and convenience that public transportation, there, won't give you.
Avoid driving into the historic core or any of the ZTL's in Florence/Firenze in Italian. It's best to arrive in Florence by train and explore this compact town (the historic core of it) on foot.
Go to CT by train and explore on foot.
There are van tours from Florence to 1) the hill country and/or 2) the Tuscan wine country.
There are cooking classes in Florence.
Siena is a good day trip from Florence. Unless you want to go to the Siena train station for some reason, take the bus instead of the train from Florence to Siena and back, and explore the historic part of Siena on foot.
There are many hill towns accessible by bus or train between Florence and Rome. Siena would be first choice, but some others are Certaldo, Chiusi, Viterbo - plus the more well-known like Cortona, Arezzo, Pienza. Google photos of various cities to see what appeals to you. Both Florence and Siena are good transportation hubs (from Siena you can easily get to Montalcino, great city for food and wine).