Italy's rail network is the easiest way to travel between cities. Download the Trenitalia app (https://tinyurl.com/trenitalia-app) to map your route and buy tickets - you can book in advance, too.
Coming from Rome's Leonardo da Vinci Airport (FCO)? In the app, search From: Fiumicino Aeroporto To: Chiusi-Chianciano Terme. The quickest option is usually the express to Roma Termini, where you'll change trains for Chiusi-Chianciano Terme.
For our American friends, go to AAA to get an international driving permit so you're able to legally drive while in Italy.
We recommend taking the train from your previous destination. The nearest station is located in nearby town, Chiusi, which is a short 20 minute drive from Panicale.