Can a quiet horizon still help the player navigate?
Thinking about distant scenery as a directional clue.
A distant horizon can make a scene calm, but it can also flatten the picture if every distant shape has the same value. In a small coastal room, the destination may need one clear break in that rhythm.
I would compare a plain version of the building against the sky before introducing mist. That gives the atmosphere something legible to soften.
When you draw fog or pale sea air, what cue do you preserve first: the destination silhouette, the ground edge or the contrast of the path?