Public Transit

Trains (Trenitalia) will get you there in as little as 80 minutes (one change in Viareggio); some departures take over two hours and require two changes, so it depends on what time of day you want to leave. It appears the cost will be under 15 euros for any departure. Departures including an InterCity leg are likely to cost a bit more than all-regional itineraries.

Trenitalia.com

That is so cool to know, thanks a lot.

If you haven't travelled by train in Italy before, there are a few caveats to be aware of. If you're using locally purchased tickets, those for Regionale trains have to be validated prior to use on the day of travel. Failure to do so can result in hefty fines, collected on the spot. Trains for the premium trains such as Freccia or Intercity require a compulsory seat reservation (included with the ticket), or again hefty fines.

https://www.rome2rio.com/map/Lucca/La-Spezia

The train most likely is the best, but not the only option

Ken,
You are saying that for Regional trains that you have to validate your tickets BEFORE the day of travel? What if you just purchase your tickets on that day?

You validate (time stamp) paper regionale tickets just before boarding the train. That time stamp provides authorities who make random checks proof of what time you got on the train and that you're not illegally re-using a ticket. It also tells them that you're using the ticket for the journey/train it was purchased for.

There is a time limit on how long a validated ticket is good for (4 hours after boarding, last I knew) which is why you don't validate them until just prior to climbing abroad. Electronic tickets purchased online are already pre-validated.

I believe this information is still correct but, folks who may be aware of more recent changes, please pipe up if it's not!
https://italyexplained.com/new-rules-for-regional-train-tickets-in-italy/

It's right, paper regionale tickets can be used on any Regionale running that route on the picked day. To avoid people re-using them, you must time-stamp these tickets before getting on.

Paper tickets are very convenient when one has no internet and wants to purchase all the regionale tickets for the following days/weeks at once.

Know too that Trenitalia has an excellent app for smart phones that allows you to search and book tickets - including the Reginales. Once the booking is confirmed the tickets are sent to you electronically and only need to be shown on demand ... either to enter the platforms at the larger city stations or on board the train if requested. The Regionale tickets come with a time stamp so there's no issue regarding validation as there is with a paper ticket.
We found the app to be very convenient during our visit to Italy last year. Give it a look.

Ken did NOT say that tickets have to be validated before the day of travel.

He specifically said:

have to be validated prior to use on the day of travel.

ON the day of travel.
Prior to use.

Paper tickets are very convenient when one has no internet and wants
to purchase all the regionale tickets for the following days/weeks at
once.

I agree, Dario! You just have to purchase them for a specific date of travel and specific journey.
And Kim's right: Ken did say. "...prior to use on the day of travel." :O)

Remember back when you didn't have to specify a date when purchasing in advance? I think you could buy them up to 2 months in advance of a particular journey and use them any time within that period.

but if you go into Trenitalia and put in Cinque Terre as your originating station it will look at you with its mouth open and a quizzical expression. There is no station by that name, it is a name used for 5 close together villages. You need to pick one, perhaps the one where you hope to stay, and type that in before you will get information or tickets out. Maybe try Monterosso.

Oooh, good point, Nigel! Monterosso, Vernazza, Corniglia, Manarola and Riomaggiore are the 5 (Cinque) lands (Terre).

I have traveled by train in Italy before, but this is all good information. The added details help a lot and will keep me from making clueless mistakes. Thanks to all.