I don’t think this is a “treacherous” route. I know a number of people who have walked the Camino dos Faros and have not heard any descriptions like that. But I could be wrong and would like to hear from members who have walked it.
I would take a good set of GPS tracks, though, because this trail does not continuously hug the coastline.
Ruta de los faros. Ultima etapa. Lires-Finisterre. Hiking trail in Lires, Galicia (España). Download its GPS track and follow the route on a map. Record your own itinerary from the Wikiloc app, upload the trail and share it with the community.
www.wikiloc.com
Good luck, I hope you find companionship if that’s what you want, but with a good GPS track you might be fine alone!