Updated 10/13/2019:
Well, chaos reigns! We pulled the bridge in preparation for working on the C&P River Route.
Construction of the River Route began with the laying down of a 5/8" piece of plywood to elevate the area. Would that be called the sub-sub-roadbed? 
Here's a look from the front and from the side along the river. We needed to match heights with table built under the layout.
That was followed by the sub-roadbed. This is another 5/8" piece of plywood cut to match the O42 curve.
Finally, I started laying track. The red wire is for super elevation.
Here's the same area from behind the Pier 7. It's a little dark, but there is an O54 switch back there. I'm planning a hidden siding on the C&P River Route.
More when I know it. 
George
