Very conveniently located, just a few blocks away from the Puerta de Atocha train station, which puts you within 40-50 minutes of the airport.
Plus there are two metro stations and several bus lines, also within walking distance. And that makes the whole city accessible from here.
There are plenty of restaurants, supermarkets and fruit/vegetable shops in the area.
The Prado museum and Real Jardín Botánico (royal botanical garden) are a pleasant 15-20 minutes walk away. Rest everything are accessible by metro/bus.
The hostess was very generous in letting me drop off my luggage, shortly after the previous guests had departed. Very much recommended.