I know Salerno has not been as popular a destination for Rick and his readers, but I wanted to share the information I was looking for when we decided to stay here.
First and foremost, it is a beautiful, friendly city. It feels very family oriented and safe. We are staying just one block north of the coast and one block south of the beautiful, pedestrian-only, shopping street that begins directly from the train station.
Getting here was easy. We took the Alibus from the airport to the Napoli train station. Just follow the signs for Alibus immediately upon exiting the airport. From there we took a direct train to Salerno. There were plenty of kiosks and train staff to help us. Note: if using the automated machine to purchase tickets, you MUST have a chip card and a PIN. I used my ATM card with no problem.
Things we learned:
To get to the beautiful Castello de Arechi high above Salerno, take the local bus 19 towards Croce. You can meet the bus at the Piazza XXIV di Maggio. We found tickets and the bus schedule at the bus office by the train station. Not much time is required to see the site, but it was beautiful and had amazing views.
Getting to Paestum is easy. Follow Rick's advice on how to arrive by train.
Getting to Pompei is actually very easy even though you are coming into the downtown station. Exit the station, walk forward looking slightly to the left. You will see the large tower of a church. Walk directly towards it. When you get to that square, follow the signs to Scavi. You will turn left onto the street on the far side of the square. In about 5 minutes of walking you will arrive at the Anfiteatro entrance of Pompeii. For us the lines were short. There are restrooms just inside the entrance. We chose to exit at the Circumvesuvania entrance as we took that train on to Herculaneum. (Yes, crazy!). We were able to catch a train from the Ercolano- Portici Station. The station was about a 20 minute walk from the ruins, but did offer direct trains into Salerno.
More later, but I just had to share how amazing Salerno is. I am so glad we chose to stay here!
I hope the information helps the next person planning their trip.
Edited for a correction and added detail.