Based on Rick's guide book and this travel forum, we hired Mondo Tours to take us from our hotel in Naples to both Herculaneum and Pompeii, where a guide was waiting for us to provide us with a private tour of the ruins. The Mondo driver then drove us to our hotel in Positano. It was a splurge but the most efficient use of our time that day, so we didn't have to backtrack to Naples to take trains to Positano.
I'm confused- Is there a train to Positano?
However, we used Mondo shared tours for Pompeii, and felt it was a great tour and value. Thanks for posting.
Nope, there's no train service to Positano.
The OP may have meant train from Naples to Sorrento...from which they would have had to have taken a bus, ferry or private driver to Positano.
We used a Mondo guide for Pompeii and she was a big disappointment. However when I contacted Mondo they refunded our money and were very upset about our experience and went overboard to make things right.