In the photo is Port Moon Bothy — a former working base for fishermen.
The hut was restored to its original form and adapted as a very basic place to spend the night. There’s no running water, no electricity and not even a road. People usually get there on foot or by water. Salmon fishing in these parts ended in 2002 because stocks had collapsed.
It stands closed now, and I couldn’t find any information on how to rent it today, but there are accounts from people who stayed there in 2015.