I am starting an attempt to put some flat against-the wall background landscape. I cut some foam shapes and have glued them together. Next will be a layer of plaster cloth to add texture and some folds along the vertical sides to give more detail interest. Then I plan to paint it to simulate rock, add some turf. I was thinking some 1-2" trees on parts of the upper ridge line, and taller ones on the lower one to force perspective.
Also added some scenery around Wally's service station. Waiting for a few electrical components to install the sound system for cars stopping in for service.