Hello, I am planning to walk the San Sebastian to Bilbao stage of the Camino del Norte in the first week of September 2018. It is hard to gauge from previous posts the level of difficulty for this stage? I am in in my late 50s and have a reasonable level of fitness. From what I have read, the most difficult stage seems to be between Deba and Markina-Xemain. Also a lot of posts refer to the mud on the trails, I would not expect this is in early September? Any advicd would be appreciated!