Hi,
I walk the Norte regularly (each summer, or Easter)as I love it so much.
Nowadays I tend to go as far as Santander.
The only real bottle necks are San Sebastian and also Deba.
Deba has 1 albergue only and access is frustrating as you must first go to the tourist office before the Albergue. The tourist office closes during the day and as such you cannot guarantee a bed until it opens they register you and give you a ticket. Opening(or more importantly closing) hours of Tourist need to be checked in advance of arriving. In Deba there is only one Pension, Zumardi, a nice place but regularly booked out.
Having said that if you organize yourself and know the timingsof tourist office
Deba Tourist Office. Deba is a coast town plenty of interesting sights. The tourist office offers a wide range of services, which will help visitors to
tourism.euskadi.eus
you should be ok as the Albergue has 56 beds.
El ALBERGUE DE PEREGRINOS GELTOKI es un albergue ubicado en la localidad de Deba, situada en Camino del Norte a Santiago
viajecaminodesantiago.com
All other stage ends , Getaria, Markina, Gernika, Bilbao etc , all have options to consider.
Also worth pointing out I mainly travel alone, occasionally, with my wife (Where I book Zumardi,Deba well in advance)
Best of Luck its a beautiful route.
Peter