Thanks to everyone for the advice about booking directly on Trenitalia.com. I've booked a couple of high-speed tix and got what seemed to be good family discounts (my husband and I are traveling with two kids under 12). However, I don't see more than one option for Rome-Assisi the day we want to travel (late June) -- and the same for Assisi-Florence. Is this because these are considered regional trains with no high-speed options so we can't book in advance? I'm OK with buying at the station there but our itinerary is pretty set so trying to save time and hassle where I can since we'll have kids in tow :-).
Thanks,
Wendy