Thank you Arimel. Yes, the white space is supposed to just be empty area (shorter grass, or maybe stomped down). I don't really want to put that in the legend, but maybe I should give it a light coloring of some sort. Thank you for the shadow idea -- the shading was just supposed to be shaded relief, but it makes sense that at the scale of this map the stones and buildings would have shadows too.

I think you hit the nail on the head with the side-view vs top-down view on the grass, that's where the biggest problem is. I was going for something like they do on some topographic maps where they use a green "w"-ish shape scattered an area to represent marshes or grass. But that's for a different scale of map, so it doesn't fit. I'm not great at drawing naturalistic features, but I'm going to have to figure out how to represent grass from the top.