We walked the Norte in 2018, and we found a lot of information about alternatives in this forum, leading to some amazing views. My advice: don't always follow the yellow arrows and check out the information here:
https://www.caminodesantiago.me/community/threads/coastal-alternatives-to-the-nortes-asphalt.49578/
We are slow walkers, didn't carry sleeping bags either. We started in Hendaye, and did a deviation to Oviedo, which is really worthwhile. Here are our stages, where we stayed and the distance in km:
Pasajes AirBnB 21.5
San Sebastian Pensión Amaiur 6.2
Orio Mailan Casa Rural 16
Zumaia Albergue Santa Klara 15.7
Ibiri Izarbide Pilgrims Hostel (this is the only dormitory, but we paid for sheets) 19
Markina-Xemein Hotel Antsotegi 19.1
Munitibar Gerrikaitz Casa Rural Garro 11.5
Gernika Pension Akelarre Ostatua 13.9
Lezama Hotel Rural Matsa 21.9
Bilbao Ibis Bilbao Central 10.5
Portugalete (via Ria del Nervion) Gran Hotel Puente Colgante 12.4
Pobena Mugarri Rural Apartments 13
Castro Urdiales (via Miono) Pension La Mar 15.9
For the next two stages, you may wish to follow the official path:
Oriñon Chez Mano, Las Campas 68, Oriñón (AirBnb) 16.4
Laredo (via Monte Candina, coast) Hotel Ramona 11.5
Noja (via Santoña) Hotel Maria del Mar 13.6
Guemes (via Castillo & Bareyo) Posada Camino del Norte 15.4
Santander (via Somo) Hospedaje Magallanes 14.6
Liencres Hospedaje La Picota 19
Polancos Rolisas 22.2
Santillana del Mar Posada de la Abadia 11.8
Cobreces Pension Bella Vista 13.2
Comillas Posada La Montañesuca 10.4
Serdio Hosteria El Corralucu 19.6
Buelna Casa de Aldea El Valle 17.8
Llanes Hotel Don Paco 17.3
Nueva Hotel Luna del Valle 18.3
Ribadesella/Ribeseya Pension Arbidel 15.9
Colunga Hotel Villa de Colunga 22.6
Villaviciosa Hotel Carlos I 17.9
This is where we dipped down to Oviedo
Valdedios Hospederia Valdedios 9.9
Vega de Poja Casa Rural El Calero 15.4
Oviedo Hotel Rosal 20
And back towards the Norte:
La Miranda - Llanera Hotel Royal 16.6
Aviles Hotel Palacio Valdes 14
Muros de Nalon Casa Carmina 22.5
Soto de Luina Apartahotel Rural La Hortona 18.4
Ballota Hotel Casa Fernando III 12.8
Barcia Hotel Casa La Fonte 21.6
Puerto de Vega Hotel Pleamar 21.3
La Caridad Hotel Rural Casa Xusto 23.1
Ribadeo Hostal Linares 23.8
Villamartin Grande Tentempe Peregrino 18.7
Mondonedo Hotel Montero 17.7
Abadin Pension Casa Goas 13.4
Vilalba Parador de Vilalba 20.6
Baamonde Hostal Ruta Esmeralda 18.8
Miraz O Abrigo Hostel 16.6
Reguela Bi Terra 14
Sobrado dos Monxes Monasterio Cisterciense de Santa María de Sobrado (in a private room, not in the dormitory) 15.8
A Gandara (Boimorto) Casa da Gandara 11.8
Arzua Cima do Lugar 10.2
O Pedrouzo Pension 9 de abril 19
Santiago de Compostella 19
I hope this helps.
Buen Camino!