lots to see in Tuscany in one month
Wow Doodles, a whole month sounds awesome! I think you'll find it difficult to miss something in a month - but one very important question: are you planning to stay in the same place the entire time or move around? Because I think for a whole month, I'd suggest staying in a different area each week and exploring the area right around each place without too much driving. In a month, you could see most of Tuscany but if you're using just one base, that will mean a lot of driving.
For example:
week 1 - near Arezzo - see Arezzo, Cortona, Sansepolcro, Anghiari, Castiglion Fiorentino, Montepulciano, Asciano, Pienza, San Quirico, Montalcino.... just to name some of the towns you can visit in the area.
week 2 - area between Florence and Siena =
CHIANTI. Explore the countryside and all of the hilltop towns, incluiding day trips to Florence and Siena. Plus San Gimignano, Castellina in Chianti, Radda, Panzano, Greve, San Donato, Certaldo, Monteriggioni, Colle Val d'Elsa, Volterra.
week 3 - Pisa/Lucca area - explore the coast around Viareggio called Versilia and visit the castles from Massa to Pontremoli. Explore the outdoors hiking around the Apuan Alps...also a day or two on the sandy beaches. Of course, explore Pisa and Lucca too!
week 4 - Elba/Piombino/Maremma - you could spend a few days on Elba and if you choose to do this, maybe I'd do this on week 1 or 2 when weather is still sunnier. Explore the villages along
the Etruscan coast including the wine region of Bolgheri. Lots of great beaches and more!
All of the areas above have their wine regions to explore... including wineries and "wine roads" ;-)