Do this--stay out of the left lane if you're enjoying the view. Use your turn signals. Don't drive too fast; if there's a crazy person in an Audi behind you (75 percent of the time it's an Audi) let them pass. Find a nice place to eat lunch. have fun.
LOL There's some sound advice in this quote. It can be pretty hard and pretty expensive to get into the heart of Tuscany or Umbria without a car. While it can be done (so I'm told), it's not quite the same experience as wandering around the countryside on your own, being able to take as much or as little time as you like at any particular spot.
I'm reminded of one of the highlights of our trip. We set out one morning, heading south from our home base near Greve. Our ultimate destination was The Abbey of Monte Oliveto Maggiore. We spent a leisurely morning exploring the charming hill town of Radda. We bought a lovely silver wine stopper adorned with the Chianti rooster. From there we wandered over to Gaiole, another charming town. We arrived at the Abbey around 3:00, just in time to see the grounds and the sanctuary. There's a nice restaurant adjacent to the grounds and we had a great homemade dinner before heading back to the Abbey for 6:15 Vespers, which are celebrated in Gregorian Chant. The sanctuary is in the late baroque style and while gorgeous, seems ornate for a monastery. There was a lady from a nearby town, the monks and us. We were invited to sit with the monks and were given service materials (which are in Latin) so we could follow along. We were even encouraged to participate in the responses! We are Episcopalians and members of our church choir where we often use ancient chants in Latin. We felt right at home.
We took a quicker route home and were back at our agriturismo around 9:00. It was an adventure only obtainable by car.