I was able to get my engines to run nicely over the two switches leading to the long sidings. The only problem was that I had forgotten to make a power connection to the left hand siding. That was quickly remedied, but I didn't have a chance to test it out until last evening.
Now it's time to get on to the next project. Should I wire in the DZ1000 switch machines or the power drops to the AIUs first? I'm thinking the power drops, so I can easily turn off power to sidings that are holding engines not in use, instead of having to lift wires. I can do all that seated on my rolling stool, whereas I need to bend under the layout to get wires connected to some of the DZ1000 drops. That would let my lower back get a little better first.