When traveling in Italy by train or bus, can you leave your luggage at train/bus terminals while you sightsee?
if you look on the web you can often find storage in smaller towns at places like the tourism bureau or a major attraction (ie. Pompeii). Larger towns often have storage at the train station. I assume by asking that you're going from A to B with your luggage and stopping at towns along the way. If you are at your destination, most hotels will watch your luggage for you if it is too early to check in.
Yes, A to B with stops along the way.