Reply to "Foam or No Foam?"

Another option is to put down a layer of carpet underpad. You can then paint it with a dirt (brownish) base colour, mixed 50/50 with water, then sprinkle grass coloured sawdust. You then brush away the excess sawdust when completely dry, and you have an instant mutli coloured ground base. I have done this all over my layout. Another advantage is that you can run wires under the underpad as needed for track and accessory power, with no visible wires on the layout.