I decided to look at an addition to the elevated ridge in the back center. The On30 now runs along a ridge, with one arm of the O passing track in a tunnel, with additional rocks/ridge and trees behind it. I am preserving the open access over the one track of the hidden RR, so that locos and cars can be easily added and removed from the layout with this vertical open access.
Makes for an interesting scenic view. The long run of elevated girder or trestle supporting the On30 for 10 feet or so, might look unrealistic, I was thinking. Still a nice long trestle and two shorter runs. Better?