The section between San Martín de Valdeiglesias and Aldea del Fresno is very comforting due to the route of the old Alberche train. The path is favorable and you simply have to maintain your inertia through the pine forests of Pelayos de la Presa and the shore of the Picadas reservoir to the dam wall, a delightful cycling ride. At the dam you have to cross a small slope and go down to the Alberche River bridge in Aldea del Fresno, which due to recent floods was under repair the day we passed. The route continues along the entertaining and sandy Camino de Navayuncosa, passing by the Palace of the Count of Caralt and following a section of the old railway to Villamanta, where we once again find damage to the road due to flooding. In the municipality of Navalcarnero we follow the milestones of CiclaMadrid along the rural roads marked with carved and sculpted granite posts with the names of the paths and roads of the municipality, on the map it says Camino de Madrid and on the stone post Camino from Valdeyeso. Navalcarnero has a stop in the square, it is monumental and a good place to have the last snack before the final push. In the Dehesa de Marimartín we reconnect with the route of the old Alberche railway, we pass over the iron bridge of the Guadarrama River and along the greenway we immediately arrive at the lonely streets of Mostoles Tecnológico. In this section, the CiclaMadrid milestones follow a rather uncomfortable livestock route through industrial estates and urban areas, until they cross the peripheral urbanizations of Villaviciosa de Odón and through the old military camps of Venta de la Rubia and the Meaques stream, they enter the Cottage.