The first module I put together was the standard sized module with the 33mm spaced double track running across. Still I didn't want it to be just flat, so I added a slight hill on the left and a small ridge across the front (which doubles as sort of a spill guard). Once the forms were glued down, I covered them with paper towels dipped in plaster. A road made from thin cardboard was glued along the inside edge, representing a sharp curve on a back road.
This module also served as a test piece to see how I was going to do ground cover. Always looking out for a cheaper way to do things, I used a mixture of sawdust, dirt, and dried tea leaves. I started out with a light green base coat of paint. Then I tried various methods of applying the "flocking": full-strength glue and sprinkling on top, sprinkling first and covering with thinned glue, etc. Since the wood glue I was using was not drying clear, I finally ended up sprinkling on a second layer of flock after gluing down the first layer.
The crushed tea leaves turned out too dark for open areas of grass and the bare areas of green didn't look good either. But after applying multiple layers of sawdust, it started to blend together and I think it turned out okay.
Around the tracks I used dirt to make the transition between the grass and the "ballast" on the Unitrack. Some dirt also got scattered in various spots to give some variety. The bushes were made from scraps of foam and scouring pads.
The caution signs along the edge of the road were made from 1.5mm bits of paper glued to floral wire. I drilled holes in the board along the edge of the road with a pin vise and stuck them down with a bit of white glue.
Still to come: trees!