Rental Car
The venue is 85 km away from Madrid’s airport, near a small village called Otero de Herreros. Driving there will take you about an hour. There are plenty of places to rent a car from, but you'll probably get the best prices here: Kayak: https://www.es.kayak.com/ Pepecar: https://www.pepecar.com/
Train
You can take Madrid's commuter train (RENFE) from the city center. It will drop you off at Los Angeles de San Rafael, the nearest large town by the wedding venue and where the hotels are located. It can also drop you off at Otero de Herreros, the nearest village. Search tickets for Madrid (all stations) to Los Angeles de San Rafael or to Otero-Herreros in the link below:
Hotel
There are two big hotels we recommend in Los Angeles de San Rafael, the nearest large town. They are close by, about a 5 min drive by car or taxi from the wedding venue: Hotel Segovia Sierra de Guadarrama https://www.google.com/travel/hotels/s/x3jeH Hotel Segovia Sierra | El Espinar | San Rafael | La Granja https://www.google.com/travel/hotels/s/qwD4D
House Or Rental
There are some rental houses for big groups available in the town of Otero de Herreros. See google doc with information in the link below: