The best way to see Italy and Europe for that matter is with your own set of wheels. I was once told by our friend Vicenzo in his deepest Italian accent speaking perfectly broken English, "Italians like the curve on their roads and their women" and from the voluptuous Sophia Loren to the hair pin turns of the Alpe di Siusi in the Dolomites there has never been a more true statement.
Renting a car in Italy is easier, cheaper & more fun than you may have thought.
To rent a car in Italy all you need is a valid passport & drivers license, it is recommend to have an international drivers license on hand as you may be asked for it. In all the years & dozens of times we have rented cars here we have never needed to show it. That being said the $10 for the document from AAA and 2 passport photos is worth the peace of mind for that off chance it's asked for. In Italy it is assumed you know how to drive a manual, if this is not the case request one up front from your rental car agency. (Be prepared to pay extra for this.)
A one week car rental with pick up & drop off at Fiumicino, Rome Airport will cost you about $156 for a run of the mill Fiat from AutoEurope, a train ticket for two to Fano on the Adriatic Coast will cost almost 120 Euro if purchased at the counter. (Note: train tickets are cheaper when purchase at the simple, multi-lingual kiosks.) Now let's just say you get to your desired train stop, now what - hoof it, taxi or bus? In many picturesque tiny towns there is little or no taxi service & slow sporadic buses (definitely without an English online timetable & route). You are confined to staying near the train stations or within a very close distance which means you're missing many hidden jems. With a rental car you just get the keys, a good map/gps (recommended for street address or finding the expressway) and hit the road!
On top of it, I recommend renting a car in Italy because it gives you the independence to travel where & when you want and to find your way off the beaten path.
Recommended Discounted Car Rental: AutoEurope