This has been a popular question on this forum during the past few weeks and there are a number of other recent threads on this topic. The following is the response that I have given to others with a similar question, and I hope that you find it helpful. Capri and the Amalfi Coast are amazing and easily visited from Sorrento. We stayed in Sorrento last March and took the hydrofoil from Sorrento to Capri on 3/25/17. It definitely wasn't 'semi-private' size-wise but it was easy to do and probably would be better than being in a small boat if the water was anything but calm. Fortunately, on the day we went the water was calm and the weather was perfect (blue sky sunny and warm - 70 F). In late March, Capri was not terribly crowded, although I would suggest trying to arrive by mid-morning at the latest so that you will have time to do lots of fun stuff, like taking the chair lift to the top of Monte Solaro in Anacapri (11 Euros) for a spectacular view, seeing the beautiful tiled floor of the San Michele Church in Anacapri, taking a 1-hour cruise around the island and right through one of the Faraglioni Rocks (~20 Euros), etc. Also, in order to maximize your time and not waste it waiting on line for buses, I recommend taking a taxi from the area where the ferry arrives in Capri to Anacapri when you first arrive, take the chair lift, see the Church, maybe have lunch there (there was a nice restaurant across the square, directly opposite from the chair lift exit), and then go back down to Capri town. As for a semi-private van tour of the Amalfi Coast, I highly recommend Mondo Shared Tours, which RS worked out a deeply discounted tour price. We took the tour on 3/24/17. Basically, it is an unguided tour where the driver of the very comfortable van drops you off in or near the centers of Positano, Amalfi, and Ravello. You arrange for a time to meet at the van to go on to the next stop. It seems like the best time to grab lunch was in Amalfi, where we had enough time for that and to see the beautiful cathedral. For 50 Euros/person for a full-day (9-hour) tour, it is an amazing price and very well worth it.