Sorry I rambled, but one of my friends just went over there, and didn't listen to much of my advice. He called last week saying his passport and 300 Euros were stolen in *you guessed it* Naples. Email me if you want any specifics. I spent 2 years running around W. Europe...
I also had my train pass, some cloths, and a phone card stolen from the Naples area. Let my guard down because we were staying in a nice resort (for once) in Capri.
The maid was the culprit we suspect. We did not expect that problem there, especially since we had been staying in youth hostels the rest of the time. Just be careful.
One rule of thumb....NEVER keep important things in a backpack. It is one of the easiest places for a pickpocket to access. Use a moneypouch that you can wear in front, under your clothes. You can buy thin ones just big enough for money and passport that aren't too uncomfortable.
We generally placed our backpacks across our fronts when we were in crowded areas, specifically on trains or buses. It makes it harder for people to take things. A friend actually had her flipflops taken out of her backpack. Why? Who knows.
There are some advantages to going during down seasons, as you can guess. We were able to get really cheap hotel rooms and hostels were generally not booked.
You can buy a Europass in the states before you leave. When I was there (two years ago), you could not buy them there. You can get them at most travel agencies. There are specific ones for the continent and for the UK.
One more note: Beware of train and bus schedules, particularily in Italy. They often dont run exactly on time (although that can be a problem anywhere). Have a backup plan. We slept in an airport, a train station, and a phone booth (dont ask) because of this. note: much of it was poor planning.
Despite what this may sound like, I loved every minute of it. It was an experience that taught me more then I ever thought. I actually studied in London and traveled on the weekends and during our two week vacation. If you have any questions about London, I could talk about my experiences for hours, although I am sure that many people on this board have been there as well.
I wish I could go back