I'm back. The stacked decks for the turnback loops in the upper left corner should work, a rise of 8", maybe 7" of space between them is good. The benchwork for that section is the same size and shape as the section in the old plan for the higher town of Thomas. The benchwork for the lower town that I already built is a mirror image of what is needed here. Mounting it or casters and having it but up against the stationary shelf is working nicely. Of course I have not put in any wiring yet, but that will be no problem to have a disconnect cable. Locking the casters has worked well for construction, but I'll find a way to latch it to the stationary part at some time. It is really easy to roll away from the wall to work behind, so a section 5 feet across is no problem when rolled out.
I like the yard on the flat in front of the canyon downgrade. I am seeing that I am able to concentrate on either the front or back when running trains, so I don't notice the other, spoiling the mountain view. The big curve at the right with the lower town of Parsons is where I would put it. That will take some thinking. I am thinking of leaving a narrower walkway for access along the 5 feet of wall from the door to the long wall. Even so, seven feet at it's widest is a lot. Too much to even have a narrow walkway behind it on the long wall. It is too big to do the roll out thing, but I would like to utilize the space. Maybe a lift up bridge allowing access into the center would work. I'll draw something up later when I have a chance.
Thank you everyone!!