I am traveling from Rome on to Sorrento with stop at Pompeii. I understand that I am purchasing train tickets in Naples to get to Sorrento on the Circumvesuviana. My question has to deal with do I purchase
One ticket from Naples to Sorrento (get off in Pompeii) and reboard with same ticket
OR
Purchase ticket from Naples to Pompeii, visit Pompeii, then purchase ticket from Pompeii to Sorrento
Also what is estimated ticket cost from Naples to Sorrento?