We took a day trip to Capri one day. You can travel to and from by boat, which takes about 40 minutes, but due to frequent stops for swimming it's more like 2 hours. Capri was quite crowded and ridiculously expensive, like an Italian 5th avenue. To be quite honest, you could skip Capri on your trip to Italy and never miss it. However the boat ride was positively lovely, swimming in the Mediterranean was so refreshing and really a highlight of our trip.
Peace out Positano!
That night we were pretty beat so we just stopped at some grocers and bough a nice assortment of meats, cheese and wines and ate on the deck of hotel. Perfect ending to a perfect day.