It is possible to take public transportation to Saturnia. From Florence or Rome, you take the train to Grosseto, then take the RAMA bus to Saturnia. It is a long trip by bus, about 3 hours, so it is not a day trip by public transportation. While the train part is easy (trenitalia.it--you can convert the site to English), the bus schedules are often confusing and notoriously subject to change. Like most travel in Italy, plan for plenty of time and enjoy the ride as well as the destination. Rather than a private driver, you might check to see if you can find a tour to the area--could be cheaper. And by the way, don't listen to those who state that no one speaks English. I've travelled extensively in Italy, especially in Tuscany and Lazio, and rarely if ever found anyone who didn't speak or at least understand English. Roads, too, are excellent and clearly marked with easily understood international symbols and city/town directions. For my money, I'd rent a car. Enjoy: Saturnia is a treat!