This place is wonderfully located. Using Madrid's Metro you can reach the center of the city in less than 10 minutes. A huge plus is having Atocha near. There's a bus that connects the airport with this train station. When you arrive to Madrid, after taking the bus, you'll need to walk only 4 blocks to get to the apartment.
Besides Atocha, you could visit El Retiro or the Museo Nacional del Prado just with a 10 minutes walk.
Yolanda is always available in case you need some advice or help. She suggested me places to visit and even brought me some coffee.
Overall, it was an excellent experience!