Train Ticketing in Italy

aside from your two trips from and back to Rome the rest of your trip will all be on regional trains. the prices on those trains don't change and if you get them in advance you add additional time restrictions you don't have when you get them just before travel, either by app or paper ticket from the station (if you do get them at the stations be sure you validate in the machine).

For the boat I just paid as I got on.

Thanks, loads. Much appreciated.

I would advise getting the Trenitalia app on your phone. You can purchase tickets any time and store the tickets on your phone. No worries about validating tickets. For the high speed trains, you probably want to purchase in advance to save money.

If you will have a data connection in Italy, I agree with Carrol. Get all tickets via app, weeks in advance (Rome-Florence-Rome) to save money and minutes in advance to save time at the counter and to avoid validating.

If not, I agree with Nigel about buying Regional train tickets at the station before getting on. I would purchase online from home only the discounted tickets for the high speed trains from Rome to Florence (and back). Discounted tickets will sell out in the coming months.

Do not forget to compare Trenitalia's and Italotreno's prices and that May 1 is a national holyday in Europe.

As others have already shared - long runs in advance, short runs at the station. All Trenitalia ticket machines at the Stations are Contactless Pay and are a breeze to operate. DON'T forget to validate your Station purchase.

Just to add: the Trenitalia app was a terrific travel tip for us. With it I was able to book trains literally minutes before we left our accommodations on the way to the stations.
Your tickets (both Regionale and Frecce) are sent to you as an attachment to a confirmatory email you'll receive once booking is complete. I'm as technically challenged as anyone, but even I was able to figure it our pretty quickly - we used it extensively during an anniversary trip to Italy a few years ago. Was nice to be able to book my tickets without having to stand in line at a kiosk at the station, and I didn't have to worry about validating paper tickets since the reservation was already time-stamped. Just need to ensure that you have plenty of battery life on your smart phone so you can show the tickets to the checker when he comes thru the cabin, as well as to the security people at some of the larger stations (SMN for example) in order to access the platforms.

If you buy and keep the tickets on your phone, take a screen shot of the tickets.
Then you won’t have to look for them with data use or look for wifi to access them.
Same for any tickets: air, theatre, concert, etc.

I would much rather have the flexibility to adjust my schedule the day before I left or even same day. Look at the schedules online.... All of those routes you mentioned have TONS of daily trains, so you'll have lots of options. No need for advance tix; especially in May.

The trade off is you'll save money on some routes as pricing is dynamic and demand driven.

Question - Why not an open jaw flight, into one city and out of another? You don't need to fly into Rome, instead fly into an airport closer to your first destinations. Saves a train ride. Just an idea......