We'll be taking the ferry from Sorrento to Naples in October. What are recommended ways to get to train from ferry dock? Is there a taxi stand at the dock?
Yes, there's a taxi rank at the ferry dock. It should cost around 13€ for a transfer to the train station.
It's a fixed rate, info here.
https://www.napoliunplugged.com/wp-content/uploads/2018/03/Tariffe_taxi_2017.pdf
Perfect, thank you!
The other option is to walk about 100 yards to Piazza Municipio and take the Metro to Centrale Station--it's the final station on the line so you'll see signs pointing you in the right direction.