Ciao Duchesse,
Sgrima has done a good job of describing the locations of the towns across Tuscany and which ones can be visited together because close to each other.
If all you have is 2.5 days, time will be limited.... I imagine you're driving from somewhere: from Rome or Milan/Bologna? I ask because it could be useful to know so that we can also offer an idea of the order in which to see things.
So let's suppose you are driving up from Rome. As you drive up, since you prefer wine and food to museums/art (you don't need to visit museums to see art since everything is like a museum ;-), I'd suggest heading west from the A1 to
Montepulciano and
Pienza and
Montalcino. This area is dedicated to red wines (rosso di Montepulciano and brunello di Montalcino) and cheese production (pecorino in Pienza) ;-) You can have lunch at either of the first two, depending at what time you arrive. Remember lunch hours for restaurants are 12.30-2.30 latest, kitchens do close! Then your choices are panini and whatever you might find at bars (coffee shops) which are the "fast food" equivalent for Italy. Then keep driving toward Montalcino - visit the Sant'Antimo Abbey nearby, truly gorgeous! - passing through San Quirico. The landscapes here are beautiful.
Then head up toward
Siena for dinner and for the night, I think it would make the perfect base for you. You don't have to stay in the city center given you have a car and don't really want to worry about the ZTL but some hotels do offer the chance to drive up to the hotel to drop off luggage and then park outside. This article has
info on parking although take it just as a guidance because it is a bit outdated and needs updating.... I think it is likely they've done away with most of the free parking :/.
In any case, Siena is a perfect base and gives you a chance to really live it better. The next day you can head toward Volterra and San Gimignano. On the way there, you'll pass by Monteriggioni and Colle Val d'Elsa, you can stop briefly.... or not, you can always head back your last day..... I'd suggest spending some time in Siena on your third day and visiting the main square, the Palazzo Pubblico, the Duomo with its nearby monuments (baptistery and climb up the facciata for the view in the museum, at the very least). Siena is lovely and many people spend too little time there. If you dedicate the day, you'll have a chance to enjoy it very much.
On your last day, if you're heading north, you can spend it in Chianti. From Siena, you can pass through Monteriggioni again, then head to Staggia (quick stop to see the castle if you want) and from there head up to Castellina - some of the most beautiful landscapes with vineyards in the area are here. From Castellina, head to Greve, stopping in Panzano along the way. If you have time, visit the tiny hamlet of Montefioralle above Greve, it is where Amerigo Vespucci's family lived. You can spend all day here or head out to your next destination by the time you need to...
There is definitely lots to see just driving around, more than there is generally time for.... so just stay flexible and see what you can fit in!!