Lee,
Been a while since you discussed "the next room" -- the one "below" on your drawing...
What about keeping the current yard for run through staging (coal/hopper trains) and put two new loop stagings in the other room, below what you already have planned for that room?
Then you wouldn't have to undermine your current scenery to make new connections, etc. It might also afford more flexibility, plus perhaps the ability to fiddle, if need be.