The bullet trains sound interesting.

Most of our experience is with Trenitalia.

We found it pretty hard to buy anything in advance and to know exactly what stations were what on their websites.

Did a enough research with Rick Steve's books and others to know which stations in Venice, Rome, Naples, Livorno, Pisa
we probably wanted to go between. We then bought tickets at the time of travel. Trains are pretty good. Every once in awhile we were packed in from say city center to suburbs and then it thins out.

I was able to get some rough timetable info. Like we better be at station by 8am.

MY BIGGEST ADVICE IS BE PREPARED AT SOME STATIONS TO KNOW YOUR MC/VISA PIN #. I never use my cards for cash. This became a problem as many machines wouldn't process AMEX and MC/VISA processed but wanted a PIN. Be sure to have some Euros on hand. None of this is a problem at the big stations that have people and funny the machines took AMEX and Visa without PIN. Must be a crdit card fraud thing at the booneyville stations.

enjoy, we would definitely ride trenitalia again.

Validate your tickets - the dudes show up when you least expect it.