Unable to answer "Is drinking water freely available for guests here?" – Zona de Acampada de La Caldera (Backcountry Camping Area) – https://osm.org/way/625016769 via StreetComplete 62.1:

No obvious camping area with water access. Only a Closed big water pipe from the mountain and a clear cut area.

Attached photo(s):
https://streetcomplete.app/p/323696.jpg
https://streetcomplete.app/p/323697.jpg
https://streetcomplete.app/p/323698.jpg