Most of the cars in Italy are small for obvious reasons, I wouldn't be concerned too much about fuel prices, just enjoy the place. Umbria is the least developed area in Italy, AFIK, very picturesque as is neighboring Tuscany. I was there a few years ago, it's one of my favorite parts of Europe, second only to Sicily. Also, the people there drive very fast - but no road rage - a reason why there are so many race car drivers from Italy.
Bring lots of film.
Paul