Updated 5/8/2015:
Here are some photos to accompany the previous update.
First, the river bottom module and its new cross-members.
Next, the regulated power supplies. 5VDC on the left; 12VDC on the right. Note that you can buy these new for very little coin. They are much safer than using unregulated computer power supplies.
Wrapped and suspended the wiring bundle under the Hidden Passing Siding. This looks a lot better to me now.
OK, now we need to make sure that the river bed module is actually level and properly positioned / attached to its legs (see Photo 1 for reference). In order to have the backdrop and bridge piers fit correctly, we will need to have the module level left to right and front to back. That's the logical next step.
George