John,
Here's a diagram to generate some conversation regarding how best to wire the layout. It is by no means the best way or the only way, just something for discussion.
As you can probably tell, I put the control panel (gray) on the yard side of things. I then ran wires to the yard and to the left/top sides where terminal strips would be. The Blue, Green and Yellow sections would be further broken into power blocks and I'd block each spur so you could store an engine on each and turn off the power. You'd also want to block each whisker track. You'd then divide the Blue, Green and Yellow tracks into blocks being sure to limit the size of each to conform to recommended DCS lengths and number of joints. Remember, these are just for power feeds, so 2 smaller blocks are better than 1 longer one.
Some folks have had success using a common ground, but DCS guidelines suggest running individual common and power feeds to each block, keeping both wires the same length. Hope this generates some comments.
