Highly recommend Stelvio’s place to stay for a Naples visit. You basically have your own apartment within Stelvio’s flat. There is one room within the apartment used by Stelvio for work but one does not really notice it / does not hear anything. Kitchen equipment could be better but you can simply ask Stelvio if you need anything specific.
Stelvio was very friendly, allowed us to store luggage on the check-out day, and even brought some croissants for breakfast as a little present.
The apartment is in the heart of Naples and also close to the central train station.
We slept well as there is no street noise coming into the room.