From Sahagun to Mansilla de las Mulas this route takes you on the more remote ancient Roman road. Calzadilla de los Hermanillos is a pretty little town with good accomodation about halfway. Mansilla de las Mulas is a gem and well worth the walk once you arrive.
I remember wanting to take the Roman road as pictured but unfortunately, I missed the turnoff due to heavy fog. I ended up walking through Option B which was still a great walk.
Thanks for sharing the photos!