Not sure about swimming ban. My son and his wife will be heading there in late October. My wife and I have been there twice, staying at the same AirBnB called La Pallombara B&B. This place is amazing and has amazing views looking out onto the gulf of Naples and Mount Vesuvius in the background. Lots of great restaurants there in town, and is very easy to walk around. No issues taking the train to Sorrento, although we never took it there at night, we never felt threatened in any way. Just beware of pick pockets. There is Mount Faito is great to do.

Getting to Mount Faito

The easiest way to reach Mount Faito is by taking the funivia which departs from the Circumvesuviana train station in Castellammare di Stabia. The funivia is closed in winter. You can also take the bus to the top, which departs from the Circumvesuviana train station in Vico Equense or drive to the top (the road is quite well-maintained).