Maria Luisa's place is a very spacious flat on the 5th floor of a block. It offers many amenities (hot water, clean towels and bed linen, TV, coffee and coffee making equipment, etc). There is a balcony with views of the volcano. The lift requires a 5 cent coin to operate during certain hours, so make sure to have spare change with you (exact change required).
The flat is ~25 mins walk from the centre. There is an ATM around the corner and some local shops and cafes (coffee and croissant for 1.10 euros). Garibaldi train station is about 15 mins walk. The bus from the airport had a very long queue, so I decided to walk to the flat. It was only 30mins, but the route is far from scenic and there is no pavement at parts of it.
Communication with Maria Luisa was perfect (check-in/-out was simple and she gave us information on local transport). Overall, we had an amazing time at Napoli and enjoyed staying at her place. Highly recommended!