Hello! The Holy Grail Path has its own association:

https://www.caminodelsantogrial.org/

Much of the route coincides with the Caminos de Santiago (Aragonés, Catalán...) There are areas that do not have accommodation for pilgrims. I recommend you contact the association to obtain the credential (it is very nice) and for useful information.

Very few people still do this route and they are eager for us to go. I will do it one day, God willing.

Greetings