Very close to the conference place is full of parks, momuments, bars and restaurants.
Short hikings are easy to organize.
The fee includes a guided tour of the Monastery of S. Lorenzo de El Escorial (See Social Events)
For a short walk we recommend:
Casita del Principe
Parque de la Herreria
At some more distance and longer walks you can find:
Paseo de la horizontal
Mirador de Abantos
For more information you can visit here(1) or here(2).
Restaurants and Bars
You can find many restaurants and bars both in El Escorial (downhill with respect to Casa S. José) and in S. Lorenzo (uphill with respect to Casa S. José).
Some infos for El Escorial can be found here