My layout area, while about half the size of John Allen's last G&D, has some similarities. It's in a semi-finished basement with a number of pipes and columns in challenging places, and since John Allen has always been an inspiration, I've definitely followed his lead on what to do with inconvenient pipes and columns.
The biggest problem has been a column surrounded by several sewage drain pipes. I've hated this area so much over the years that I see I've never taken a full-on photo of it in its natural state. But here's a view that shows part of the problem from 1995 in an early phase of layout constructon:
As you can see, track and roadbed dodge around the column and pipes. My basic approach was John Allen's, which I've used throughout the layout: cover the columns with scenery or tall buildings. Here is an example of a column concealed in a geologic feature called the Devil's Post Pile on the G&D, from a photo I found on the webz:
I've gradually worked my way into surrounding the pipes with a big rock formation. The track next to the wall in the top photo goes into the Moffat Tunnel on my layout. Here is that track seen from the opposite direction with more scenery work under way:
And work under way to create a big geologic feature to cover the whole horror, at least as much as it can:
Over several years of very slow work, I've covered things with plaster cloth and then added rock molds at variouis times. There's an added wrinkle to scnery work here, in that my idea is to have Eastern style scenery on the left of the mountain, and Western style scenery on the right. Here's the current state of the Eastern side:
My inspiration here is to follow generally locations in the Breaks Interstate Park in Kentucky and Virginia like the scene below:
Clearly I'll need to add a lot of clump foliage.
The other side of the mountain, with Western scenery, will be based on the Castle Gate area in Utah. Here's an 1898 color postcard showing the area that I found on the web:
I frecntly found a Woodland Scenics product, Woodland Scenics "Shelf Rocks" Ready Rocks, which are precast and prepainted plaster. I've used rock molds that I pour and add myself for many years, but these turn out to be a lot easier, and the rock pattern looks like something I can use for the Castle Gate side of the mountain:
I attach the Ready Rocks to the plaster cloth with Scultpamold colored with cheap acryics added and mixed with Elmer's glue. There's more work to be done, but now I have a basic plan of attack for finishing the area.