You might want to look at Google Maps and come up with specific cities you'd like to visit. I also use Wikipedia.com to investigate all cities as I plan trips. Sounds as if you have plenty of time available.
The most popular Italian travel cities seem to be from Rome to the north. I'd be looking to fly from Sicily to Rome.
Just over an hour (by train) north of Rome is Orvieto, and it's a very popular hilltown--and a good place to pickup a Hertz car rental (across the street from the train station.) To the north are the popular cities of Assisi/Perugia, Sienna, Florence, San Gimignano, Volterra, Lucca, LaSpezia and the Cinque Terre and Turin in Italy.
Then you could turn in the Italian rent a car and catch either a train or bus into Switzerland around Lake Como/Lugano. Switzerland has really good train service going to the more popular areas.
Looking for agriturisimos and bed and breakfasts in Italy is very easy on Booking. com or even Agriturisimos.com. Virtually every farm in some Italian regions have rooms and apartments for rent as a source of secondary income.