You'll probably have to plan your own version as there will be parts where you will have to go offroad. It's simply the geography of the area.
The Spanish Depart of Transport (DGT) have a site where it shows you, in their expert view, might be unsafe which is what I think you are concerned about. Have a look at their take on the Norte
caminodesantiago.dgt.es
It shows caution points and risk points. These are the sections you either need to take care or route around - which might be difficult.
Are you going to use maps or gps?