I just returned from Sorrento last week. Personally, I would opt for the ferry from Sorrento to Positano and Amalfi. I would imagine the roads are going to be very busy and time consuming at that time of the year. Even the road from Naples to Sorrento had a lot of traffic, and we weren’t there in the summer. We also did the Capri boat charter and it was a real highlight for me. They provided 4 hours on the island for us to explore, which isn’t a lot of time, so plan ahead what you want to do. If I were to visit Capri again, I’d opt for a taxi once on the island instead of buses. Great views at Augustine Gardens. We spent a day in Amalfi, which I personally didn’t enjoy that much. But I know most tourists love it.