I will be leaving from Naples on 10/2 and wanted to know if I can go direct to Florence via high speed train or do I need to change trains in Rome? I would like to go the fastest way possible. Also, what's the best way to check schedules and prices? I tried trenitalia.com and kept getting "no solution found" even for Naples to Rome.
Hmm that is strange. Something seems to be wrong with the site for sure. I was just checking the other day and it worked fine. I would give a day and try again before making other plans. Better answer - use this link: http://www.fsitaliane.it/homepage_en.html Just found many times (about once an hour), 3 hour trip, 68 euro 2nd class on the Frecciarossa I think they are guilty of multiple websites - with some of them no longer working properly.
I have actually done this. I took the Eurostar. I stopped in Rome and then on to Florence.
One thing to check is to make sure that you've got the right train station picked on the Trenitalia site. I just searched for your cities and date and got a direct train almost every hour. Napoli Centrale to Firenze S.M. Novella
There are numerous high-speed runs from Napoli Centrale to Firenze S.M. Novella each day. These certain high-speed runs are non-stop to Rome Termini and then non-stop to Florence. Trip on the Frecciarossa (Red Arrow) @ 180mph takes 3.0hrs. Base fare is 68Euro but you can get fares as low as 9Euro if you are willing to lock into a specific travel date and time in the future and accept non-refundable and non-exchangable tickets.
Try also the new train operator in Italy, called Italo Treno.