Pisa is, indeed, well-travelled, and not as interesting for tourists in my opinion (other than the leaning tower and adjacent buildings, which are a mass of tourists). I drove around Tuscany for about a week once, and my favorite slightly-less-well-travelled place was the ancient Italian hill town of Volterra. Small and authentic-feeling (not as touristy as, say, San Gimignano), famous for alabaster carving, with bits of ancient Etruscan ruins in and around it. No big-name sites, but a cool atmosphere for wandering around for a day or two (including the surrounding countryside with its Etruscan bits).
If you're near Naples, the palace of Caserta is well worth a visit - huge palace (it was created in order to compete with Versailles) with huge fountain-filled gardens. A short train ride from Naples, and not too many tourists seem to know about it. Of course, Pompeii or Herculaneum are also a short train ride from Naples, and really cool, though full of tourists of course.
I haven't been there yet (I plan to someday), but a little south of Naples is Paestum, which has some really impressive ancient Greek temples.
Web searches should turn up more info on all these.