If you are someone who enjoys having Guide Books and Maps to pore over ahead of time, here are a couple of suggestions. I will say each of these took quite awhile to reach me since they’re being sent from overseas.
1. You want a guide book for the Northern Caminos (not for Camino Frances or any other Camino route).
The one I have is through Cicerone. Its called Pilgrim Route The Northern Caminos. This is the most recent edition of this book.
2. Also from Cicerone is a guide to the Picos de Europa.
3. The maps I have are from MAPS Worldwide.com
We will be hiking in the Central and Eastern portion of the park. Be sure you order the correct map. There is a similar one for the Western (Occidental) section.
4. Undoubtedly you will find other excellent resources, please feel free to share these with the group.