spent some time cutting the horseshoe area to shape. styrofoam is really easy to work with. but the mess it makes is exceptional gadzillions on tiny white styrofoam balls everywhere. my poor old vacuum cleaner had a hard time cleaning the whole mess.
once i was more or less happy with the shape i prepared the areas where the tunnel portals will be located. then i installed the "inliner". the what ?? i use chooch rock flexible rock walls for all the rocky parts of my layout. to make the inside of the tunnel more realistic i use a piece of these rock walls, bent to a u-shape. using some darker grey than the surrounding rocks improves the impression of depth. so if someone looks into one of the tunnel he/she/whatever will see dark grey rocks. usually 1-2" deep. so far i worked worked on 4 more tunnel portals this week. 3 are finished, just need some more painting. one portal is in place but misses all the rocks around it. two more portals need to be done completely. once all portals are in place, i will start building the landscape using the usual putty.
the following pics give an impression of "tunnel view" ...
overview of the whole area. two tunnels front left done. one in the left center done, the one in the right center needs rocks. the two at the top right need portals, inliners, rocks.