I had a shoulder replacement before Christmas, so I tackled a couple one-armed projects close to the edge of the layout. I have ceiling tile on top of foam, so I just dug in for the little stream. Shaped it with Sculptamold, painted it brown, and added stones and gravel I have sifted out of driveway stone and sand. Sealed it with diluted Matte Medium, and poured Envirotex lite.
The road is just foam core with Dennis Brennan's suggestion of Durham's Water Putty painted with Asphalt coat with a little gray added. Auto pin stripe for the center lines. Culverts are 1/2" electrical conduit.
Photos shortly.