i've not yet been to italy, but everywhere else i've been, it's pretty simple to take a train from city to city (or even cheap airfare), and then take a local train, bus, tram, or taxi (rarely) to where we want to go.
we did this from barcelona to madrid (flew), then bus from madrid to grenada, bus from grenada to cordoba, train from cordoba to sevilla, and train from sevilla to madrid.
the bus we took from madrid to grenada was pretty awesome, actually. the seats were leather, and leaned way back; there was even a "stewardess" who brought snacks and drinks out. also, it had free wifi.
i love not having to worry about parking, etc. that comes with a car.