Trains from Rome to Cinque Terre to Venice

The easiest and quickest option on that route is to use one of the direct trains that travels from Roma Termini to La Spezia, and then to Monterosso. A good option would be the departure at 09:57, arriving 14:22 (time 4H:25M, 1 change at La Spezia).

At this late date, all the discounted tickets appear to be sold out, so whether you buy online or at a ticket office or Kiosk, the price is going to be the same. In the same situation, I'd just buy the tickets from a Kiosk at Roma Termini the day prior to travel. Note that the second segment of that trip is via Regionale, so you MUST validate the ticket prior to boarding the train on the day of travel, or risk hefty fines.

is it better through Florence or Milan on the journey from Cinque Terre to Venice?

This trip can from just over 5 hours to almost 7 hours depending on the routing. On Trenitalia.com I see a schedule June 1 leaving Monterosso at 9:03 through Pisa, where you change trains to Firenze where you change again to arrive Venezia Santa Lucia as follows:

09:03 dp Monterosso 10:17 ar Pisa Centrale

10:32 dp Pisa Centrale 11:32 ar Firenze S. M. Novella

12:15 dp Firenze S. M. Novella 14:20 ar Venezia S. Lucia

There are still super-economy tickets available for the last segment if you buy now. They are non-refundable, however, so you have to commit.

As this is your first international trip I'd just go from Monterosso to Venice via Milano Centrale: only one change and reserved seats all the way to Venice SL.
If you're interested in shopping, paintings and/or Gothic cathedrals you could leave your bags at Centrale's staffed deposit and spend some hours in Milan.

We just made the trip in April from Vernazza to Venice, spent the night in Parma. We went to La Spezia , Parma (spent the night) , Bologna and Venice. Bologna was a nice break, we left our bags at the train station and walked into town and ate lunch, allow about 1 1/2 - 2 hours, then we took the fast train from Bologna to Venice . .. the fast trains cost more but they are much nicer and have WiFi which was kind of cool.

Use https://www.lefrecce.it for local trains, very helpful as you can download schedules to your phone and buy tickets online. Have the train schedules on my phone was really nice .

darioalb came up with a solution I did not see. For your ease of reference

10:54 dp Monterosso 13:50 ar Milano Centrale

14:05 dp Milano Centrale 16:40 ar Venezia S. Lucia

Cost is a little higher and it takes a little longer, but it is easy.

Thanks so much for the suggestions! To clarify, I can buy tickets at the Roma Termini up to the day before for the Roma Termini to La SPEZIA. Is it via Trenitalia? The second portion from La SPEZIA to Momterosso is Regionale?

Then, the next train from Monterosso to MILAN to Veneziia is also Trenitalia?

How soon before departure do I need to get to the train station (security, lines, etc.) I also realize I have to validate the ticket prior to boarding, please help with any other tips?

Again, I realize this is very basic, but the thing I am most concerned about! Thank you for the kind responses.

mhawkins,

Regarding your most recent questions.....

• Yes, you can buy tickets at Roma Termini either from a Kiosk or staffed ticket office. You can buy on the day of travel, but I'd recommend buying at least the day prior to travel so you don't have to deal with that when you're hauling luggage.
• Yes, that's via Trenitalia.
• The train from La Spezia to Monterosso will likely be a Regionale, but it could also be an Intercity. You can check the Trenitalia website to see all the solutions. The trip from La Spezia to Monterosso is only about 22 minutes.
• If you're travelling to Venice via Milan, you will again be using Trenitalia. The trip from Monterosso to Milan will be via a combination of Intercity and Regionale trains, and the trip from Milan to Venice will be via high speed Freccia train.
• I normally try to get to the station about 30 minutes before departure, as I may want to buy a Panino or whatever for the trip. There are not really any "security lines" but I believe they now have security gates installed at Roma Termini, but once you show your ticket you should get through those quickly.
• You only have to validate locally purchased Regionale tickets, and not tickets for Intercity or Freccia trains. The latter two types have compulsory seat reservations which are specific to train, date and departure time, so can only be used on the ONE train specified on the ticket. On the fast trains, you'll have an assigned Car No. (Carrozza) and Seat No's. (Posti).

Are you clear on how to reach your hotel once you arrive in Monterosso?

I can buy tickets at the Roma Termini up to the day before for the Roma Termini to La SPEZIA.

At Roma Termini, at any other Trenitalia station and at travel agencies that display trenitalia's logo on the window. You don't have to go to Termini station, if you pass by a travel agency. They can charge a commission, but it's usually very small.

Then, the next train from Monterosso to MILAN to Venezia is also Trenitalia?

Yes. Each day Trenitalia runs some direct Intercity trains from Monterosso to Milano. They also run those going to Venice.

I also realize I have to validate the ticket prior to boarding

You'll have to date/time stamp the ticket from La Spezia to Monterosso, the only Regionale train you could take.

As a rule of thumb:

• ticket purchased on-line = no need to validate anything
• ticket purchased locally, there is a car & seat number written on it = no need to validate.
• ticket purchased locally, no reserved seats = validate before boarding or you'll be fined on the spot.

"Locally" means at the counter, at a travel agency and at those tobacconists that sell Regionale tickets.

Thank you for the feedback and alleviating stress!