Like most warm-weather countries outside British influence, dress is informal. Because of the dry climate, clothes washed at night in your hotel usually dry by morning. Running shoes can double as walking shoes, although I packed a second pair. Shirts and singlet are sufficient. While women sun-tanning topless on the beach are not considered indecent, a male running shirtless may attract whistles of disapproval.
Streets are narrow and cluttered with cars.
On one trip, we stayed nearly a month in a small town named Fiuggi south of Rome, and I never saw a runner until one day I visited an untravelled side road and spotted half a dozen. Italians know the best areas to run, but you'll find them only by luck, or by knowing an Italian runner. Best advice is to relax, content that all the walking done from church to museum will keep you in shape until you can find the occasional convenient running area like Rome's Villa Borghesi. Surround that with antipasto, salad and fruit, and a meal can last several hours. Usually, I skip around the menu, ordering a first plate at one meal, a second plate the next.