Gotcha. Accommodation is very sparse, with one casa rural in Cubillo del César. And I think that if you go on a weekend, or worse a holiday weekend, you are going to have an issue.
There are a couple of options a little off route that might work.
VN stayed in “Pension Casa Julia in Villaespasa because the one in Mambrillas was full...only 15 € for the very nice room and they picked me up.” (quoting her thread on her San Olav).
Reb and I stayed in Hostal Moruga. We called, and they also came and picked us up. We had walked from Santo Domingo de Silos that day and made it over the ridge from Covarrubias and down to the highway (N-234).
If it were me, and it’s not, so it’s really none of my business, but I would be much more interested in making sure I got to visit the inside of the visigothic church in Quintanilla de las Viñas than the San Olav shrine. I understand that the 21st century post modern chapel has an aesthetic that I just don’t appreciate, no matter how hard I try.
Hoping it will work for you,
@chris