Peering into the tunnels from various angles, I didn't like seeing layout framing, so I extended some of the cardstock-printed rock walls. My thought is that since I've got nice LED headlights on the locos, it'd be cool to see those headlights reflecting off the rock walls inside the tunnels, as the trains come thru. And - it's really easy to add more cardstock walls.
One of the tunnels leads into a two-track hidden staging area, and because the location is somewhat awkward, I had to use a wide two-track portal. It's an AIM portal, and I did cut the bottom somewhat, to lower it. Even then, the opening was huge. So - inside I used an actual rock mold for the most visible part of the tunnel lining, and transitioned further back to more cardstock printed rockwork. It's nearly impossible to tell the difference now, looking into the opening. My thought is that if the eye sees real rock in this view, you'll hopefully be more attuned to 'seeing' the printed rocks as real in other portals.
I've also been working on the landforms leading the tunnels - trying to convey the impression of track truly burrowing into hillsides or mountains, rather than just arriving at a vertical hillside and going inside.
Below are more photos - so you can see for yourself my progress. These are a couple days old; I was able to complete initial plaster cloth covering for all of this earlier today.
Here's the longest tunnel lining -
And here's the area leading to this portal. Above, the line running above Dolores has been partially hidden, and runs into a cut before entering Rico (which is the town above the hidden track for this tunnel).
And here's thet track that's running above Dolores, after leaving Rico thru the cut:
At the other end of Dolores, are two tunnel portals - one into staging and the other being the main line as it leaves Dolores. Above, mostly hidden, is the north end of Vance Junction. I tried to visually separate all of this as well as I could.
A problem here is the track from both Dolores (lower) and Vance Jct (upper) entering a hidden area before going thru the room's wall and behind the furnance. This is already hard to reach, and I couldn't completely block it with scenery. My attempted solution is an access door, hinged. I hope that with scenery around it, the door will be invisible.
The area directly above the door, operationally between Rico and Ophir, is Lizard Head. The track simply curves around the corner here, but my plans are to build the Lizard Head snowshed here, with the shed showing a wye, even though the track will actually pass thru only one leg of the shed's wye. This is pretty high and a couple feet from the aisle, so it'll be a background scene.
And inside that door, you can see more of the printed rock tunnel lining. As before, it's arranged to show the rock as loco headlights illuminate the tunnel when they pass thru it.