Elvira runs a lovely, authentic AirB&B experience where you have the opportunity, should you wish, to connect with her and experience more of the culture and hospitality that Madrid has to offer. Unlike many other AirB&B's that I've stayed in, Elvira's place is her home, however she is respectful of your needs and schedule and enjoys welcoming people into her space.
The apartment is spotless, cosy, close to the park and shopping / eating areas in Salamanca and within an easy walk to the other parts of town that you may want to visit. The garden terrace is super (although I spent too little time enjoying it) and the neighbourhood is full of quirky bars and restaurants that should be able to cater for most tastes.
I enjoyed my stay at Elvira's and if you have an open heart and relaxed attitude, you should do to. Enjoy your trip.