My family will be in Sorrento in mid-May. After a night's stay in Sorrento, we plan to travel on to Florence and we have toyed with the idea of catching a boat back to Naples instead of the train. Is that a good idea and how far is the train station from the marina?
We took the hydrofoil from Sorrento to Naples last May. It took us approximately 45 minutes. We then walked out onto the street and caught the bus to the train station. It took us 15-20 minutes to do that. It would take you about 30-40 minutes to walk. It is not a very direct route and I really wouldn't do it. You could also catch a taxi. Depending on your family, it could be an adventure or a hassle.
That was the single scariest taxi ride my wife and I have ever been on. At one point, the cab driver was driving on the tram tracks directly towards an oncoming tram. I'd definitely take the bus. But, from Sorrento, the Circumvesuviana train is much easier and brings you right back to the Naples central train station. Minimize your stress. If you're hankering for a boat ride, use one to get to Positano or Capri and back.