Driving in Italy can give you headaches, even more in big cities (like Rome, Milan, Florence and NAPLES!) where the traffic is chaotic and there seem to be no rules!
I would recommend to travel by train, if you're travelling from one big town to the other. If you want to visit small villages and can't do without a car, watch this video for some advice:
Some videos about driving in Italy:
Driving on the Amalfi coast
Driving the Stelvio Pass - One of the Best driving roads