Thanks for the tips! I tried the inner/outer glow method, but I think my A5 room makes it difficult. When I fill the selection, the narrow corridors are all filled in to the point blurring it doesn't help.

The way I was doing a drop shadow was giving it 0 for the offset so it was as if the light was straight above the image. I played around with that some more... made them wider and added a couple... looks a bit better now, IMO.