After additional massaging, the color hues begin to conform to the objective.

Next up is to create the scene break between this element and the next - a set of tunnels to enter and exit a horseshoe canyon where the track transitions from the upper to lower level.

The PVC pipe is temporarily holding the screen canopy out of the way (the canopy providing welcome shade during the Phoenix summer).

This is the tunnel area after the initial wash of basic beige color.  When dried, additional  cement/stucco caulk comes into play to hide seams in the extruded foam.