Hi, we will be staying at Hotel Helvetia in Pisa (near the Tower), and then we will take the train to Vernazza. It looks like "Pisa S. Rossore" is the closest train station for us, about a 20 minute walk from our hotel. But the Google map street view suggests that the suggested Google walking route is closed off(?). And anyway, I'm wondering if this is a full service station where I can buy tickets. Does anyone know anything about this station? Or should I take a cab and go to Pisa Centrale station instead?
I believe Pisa S. Rossore is a smaller station and will likely have Kiosks to purchase tickets but I doubt that it will be "full service". You can certainly use that as a departure point to Vernazza, but the quickest routes will likely be from Pisa Centrale. There will usually be one change on that route at La Spezia Centrale. Be sure to check which type of trains you'll be using on the Trenitalia website. If any legs are via Regionale, you MUST validate your tickets prior to boarding the train on the day of travel or face a hefty fine.
Remember that you can buy domestic Italian train tickets at any station in Italy. So, if you are using the Pisa S. Rossore station and are worried, simply buy your ticket from there to Vernazza before you get to Pisa. It's easy in the machines; they will default to "from" (origin) being the station you are in, so you just change that before selecting your destination.
If you have trouble climbing up a very steep incline step, you may want to use Pisa Centrale rather than S. Rossore. I am not kidding, it was difficult for me. One woman, a little shorter than I am (5'2") had to be hoisted up by other passengers.
I took the train from Lucca to Pisa, and hopped off at the San Rossore station because It was closer to the sites. As I remember, it was more a stop than a real station. I believe there was no staff there. I don't think that all trains leaving from Pisa Centrale stop at San Rossore, so you should check carefully about that before you assume you can board the train you want there. I myself walked through the town to depart from Pisa Centrale, but then I did not have any baggage with me.
Thanks everyone, your information is very helpful. All things considered, I think we will go to Pisa Centrale station. And now, looking at the map again, I see that it's not too far from our hotel, maybe a 25 min walk or a quick taxi ride.