Hi, forum friends,
I left my Baztan amigas in Pamplona and I'm now walking the Norte. I will try to post a few comments that might be helpful, but I'm sure you don't want to hear my blow-by-blow account of this very heavily traveled Camino.
Day 1--spectacular walk into San Sebastián. At the Guadalupe sanctuary, there is a split. My recommendation is the so called Alpine route. It is perfectly doable, no scrambling involved, and the views are great.
After the ferry, you will go up again. And about 4 km outside of San Sebastián, you will see another split. The Camino route goes left, and up to an asphalt road, while the GR sign to the right is on a beautiful dirt path through forestscand along the coast. There is absolutely no comparison. Take the GR 121.