Added dirt and some vegetation today. The dirt is sand from the Lockwood Valley. If this was a working layout I'd be somewhat hesitant to use sand as ground cover, for fear it might find its way into locomotive mechanisms, but this is a mostly passive diorama, so not much of a concern there. The vegetation is Woodland Scenics and other brands of ground foam. I plan to add other plants, including some fake fur grass tufts and sisal twine reeds at the bottom of the slope. The background hills are coming out very blue in all my photos. I installed LED tape lights, which are giving everything a bluish cast that I can adjust for in software, but I can't seem to eliminate in the background. I may try swapping the cool white LEDs for warm white. Update: Now that I look at it, I think the problem is that I got carried away with the black wash on the background hills. They really are more grey than tan. I'm considering whether to repaint with the tan paint, then use a red-brown wash...