The brother of Mariano was waiting for us on arrival, he showed us the house and also gave some tips about getting around, and during our stay our hosts were always easy to reach. The flat is well located if you want to travel around a bit, in 2 minutes from one train line and maybe 10 minutes from the other, "Cumana" train line. There are supermarkets and a nice pizzeria just a stone's throw away. We went to the beach in Pozzuoli (3 stops by train) but there is also a beach in Bagnoli itself. From Pozzuoli one can also take a ferry to some of the islands nearby.
The apartment is spacious, the terrace is amazing, and having a second smaller terrace for hanging up clothes to dry was very handy. The house and the flat has its charm, with a mix of older furniture and newer things. The only not so practical thing was the lack of a shower curtain and that there was no place to fix the shower head. Otherwise the apartment was really good, with a lot of space for our things and suitable for cooking (a big fridge and a gas stove, kitchenware etc). The mornings and evenings on the terrace were amazing. We spent two weeks there and had a nice time.
I would recommend this place for short- and long-term holidays in Naples region, especially if you want to move around a bit.