I'm currently doing the Camino del norte, starting from Santander, and planning stages. Although the albergue at Santander was open and another was open between here and unquera I will say a lot, maybe even the majority of albergues, are closed. This means you either have to stay in normal hostels, where those exist, or more expensive pensiones, posadas etc... It's also worth noting that these sell out, many many places I checked had no availability this Friday. So yeah, book in advance and be aware that the Camino will likely cost more than you expected because many albergues are closed and any other options are 2/3/4 or even 5 times (or more)as expensive as those.