Thanks Jim, I am finding that using 2" thick foam as the layout base is a wonderful thing.
Miles, the paint on the foam is gray. I'm trying to model the color of the earth around here, which is mostly gumbo clay. Now, I had originally started out with tan, but it looked like desert. Then I had Home Depot mix me up some brown, but it was too dark and, well, too brown. Then I got the gray that you see, and it was too gray. My latest is, I mixed the brown with the gray and that's what I have now.
I am posting pics in a new thread, so see what you think of the color. I'm still not completely happy, but most, if not all of it will be covered with grass bushes road gravel trees ballast.