So I decided to go with the 75% opacity on the outside shadow layer. After messing with a few other options and testing out percentages between 50% and 75%, I liked that one the best. It is a *little* dark, but it shows some of the shadow variation I added to the ground and the border around the house without being too dark.
After that decision was made I started to shade the decks and stairs on the outside of the house. I had originally planned to use the flat-topped posts on the deck railing as full-height (going to the roof over the covered deck) and not shade them the same, or at all, compared to the rest of the railing. But when I did that, it stuck out so much that it took away from the look I wanted and distracted from the shading, so I ended up shading over the whole railing and the whole deck in the same tone. I think I've achieved the "dark and moody" feel that I was going for on the outside, but still have some details and variation to add. Any comments or critiques of the shadows/shading on the outside is welcome!
Then, with the outside *relatively* finished, I started to work on the shadows indoors. Since the outside became much darker I had to start over on the indoor shadows and darken them quite a bit. I am planning on adding a few more light sources in most of the rooms so that it is not entirely shadowed, but I am still going for a "gloomy" look on the interior. The shadow on the inside is the tone/level of darkness I think I want to start with and then add darker shadows around objects and light areas around candles and lanterns and such and I still need to figure out how to add the second floor balcony shadow around the front room.
As of right now, I do not plan on shading or adding shadow to the walls or the doors. Any opinions on that would be appreciated since I don't know if having those pieces at full brightness takes away from the darkness in the rest of the house.