Met a Hungarian pilgrim in Padrón who did the coastal route plus the spiritual variant from Pontevedra. She said none of the albergues were open on the spiritual variant, so she stayed once at a hotel, and once she called the albergue and got them to open just for her. The boat for the last part does not operate until March, so she walked the whole thing—45 km today! Along the coastal Camino, she said some of the albergues were closed, so she always called ahead to find out where she could stay next. Her daily walk ranged from 22-45 km between open albergues. So the coastal route in winter is probably best for people who are prepared to walk long (and after dark, since the days are short).
Hm, we had a totally different experience there last year. When we walked there in Jan 2019 all the albergues were open on the Espiritual, at least the municipal ones where we stayed, and they were of excellent quality. The one in Vilanova de Arousa was definitely year-around, it had a very dedicated elderly hospitaliero there, and it was the hottest on the whole Coastal way! In Armenteira we had to call for it to be open, there was a phone on the door of the albergue, the woman with the key came quickly.
Re the boat: it did operate throughout the winter months but the price was very high out of season, it was quated at 150 euros for a boat, there were 3 of us there at the time but as we walked on a budget that wasn't an option for us. For others it might be though. So we walked to Pontecesures instead, that's 32km, there is an excellent municipal albergue there so was no need to be walking thurther 4kms to Padron.
Regarding all the reast of the albergues on the Coastal: all the municipal ones were open a year ago and we stayed mosly in them adding 1 provate in Mougas. We have never called ahead and never booked anything. We mostly followed the
Brierley's stages and the longest we did was 37kms once as other options felt too short. We came before dark then, so never had a problem of walking a Camino in darkness. Actually most of the stages on this winter Camino felt a bit too short for me.
We met 2 other pilgrims on the Coastal way, one in Vila do Conde, another one in Marinhas, they were not a part of a group, walked separately, but we managed to form a Camino family there and walked with them for several days. It definitely proves to me that we all have our own unique experiences on the way!