I got to the secret room. Hint: it's on one of the pathways on the bottom floor. I don't trust it saying there's nothing else to do here....
I get the feeling Generic Fishing Game (it was even more relaxing than advertised) and my shenanigans in Lampyrid Fog have caused some trust issues with my audience. And it's very entertaining.
For real though, that's all the secrets in Scorched Sea.