Bryce, I've tried two different approaches in Photoshop using levels and brightness/contrast. The results are very different and only represent two possible results using both those methods. Personally, I like the darkest one but that's only my preference and has no bearing on your original intention which was I think to create an image reminiscent of traditional Chinese landscape painting?

Details are enhanced with added contrast.

The image reminds me of the overcast Oregon coast from Astoria down with mist rolling in which is how we saw it in last October - just beautiful!

The original image

Adding brightness and contrast (Image > Adjust > Brightness/Contrast)

The result

The untouched image and its histogram in Levels (Image > Adjust > Levels)

The histogram after using Levels on the image

Using Levels: the result

This last one could have stepped straight out from the pages of Jane Austen's Wuthering Heights - it has a dark, brooding quality that I just love.