I'm heading to Florence/Tuscany in three weeks and will take any more specific suggestions, especially regarding what to do when not in Florence. We're flyring in and out of Florence and spending five nights in the area. I think the first two nights are booked in Florence, but other than that my parents are still working on the itinerary. I'd especially love to hear about the best way to see the hill towns and vineyards, and which ones to see. Thanks!
There are probably tours you can do/take from Florence that will help - but I found driving was the easiest way. The roads in Florence/Tuscany are not bad at all (do not take a car to the lakes region or to the Amalfi coast, it is not worth it).
If you have a car, just pick a couple of places you want to hit each day and you can usually park and walk around - there are no issues with parking outside of major cities. Places to hit in Tuscany off the top of my head:
(1) Panzano - love this town, my preference would be for dinner so you can go to Solociccia - one of the best meals I have ever had - it is an 8 course all meat meal, run by a butcher (Dario Cecchini). The town is up on a hill over looking the country side and is absolutely awesome.
(2) Hill Towns - most are cool, but pretty far from Florence - someone said San Gimignano, also Montalcino & Montepulciano are awesome
(3) Banfi Lunch - Outstanding meal/wine pairing at Castello Banfi, which is absolutely beautiful. Best big winery visit.
(4) Castello di Brolio - inventors of Chianti, the castle is cool - the wine is good, probably not the best, but good and they were the inventors.
If you can stay other days, I would head south, maybe stay in Sienna - which is great, but you don't need more than one day here, and you are missing the horse race, so it shouldn't be too crowded.
Also, forgot, in Florence, go to Cantinenta Antinori - the food is pricey, but good - and you can get any Antinori wine by the glass or bottle, which, in my book, is close to the best in Tuscany.