One of those hate it or loath it jobs for most people. I'm ambivalent about it. These days with DCC and no bloody control panels its so much simpler.
The boards for the module are simplicity in itself.
All the droppers were soldered to the underside of the rails when the track was laid. Brown to the left,blue to the right rail, and the left over earth green is used for the switch frogs. No bit of rail is more than about 2' from a feeder.
I just run 1.5mm mains cable from end to end. All of the feeders are then connected with IDC Scotchlock style connectors. No soldering under the boards apart from connecting the frog and feeds to each tortoise motor.
Since I use Digitrax and most of the Freemo meets will be using Lenz I've run 2 network busses through the module. I kept these modular with RJ12 connectors and straight through couplers. This means I can operate the switches with a Digitrax throttle connected to the loconet and the trains are run through the Lenz throttle bus and track power. Being modular I can also patch the 2 network busses together so if the Freemo meet is running on Digitrax I can connect the throttle ports to the external bus.
At the bottom of the first picture you can see a pair of green/yellow cables. These are used as jumpers so that it is impossible for me to connect my own power to the module at the same time as it's connected to another DCC source. Easier than mucking about with switches and totally fool proof. It also means that if the Freemo layout is running on Digitrax I can power my own module independently by switching my DCC setup to booster mode.
All of the rest of the wiring is telephone or data ribbon. 4 wire for the tortoise motors, 6 wire for the network busses, and 8 wire to connect anything else between boards on the module. Again no soldering apart from connecting the tortoise motors. The DS64 in the top picture has screw connectors or RJ12 for everything. I don't use track power on the accessory decoders but prefer to power each one with a 12vdc supply and send the turnout commands via Loconet. That means if track power goes down as a result of a short from a loco going the wrong way onto a turnout, I can still change the turnout.
I'm also a firm believer in colour coded wiring and not keeping things too tight. Having done a fair bit of network and telecom wiring in the past, I've learned to always leave some slack, and never bend a wire to a sharp 90 degree.
So wiring boils down to this.
brown + blue = track power
green = frog
white 4 wire ribbon is for tortoise (yellow + black = power, red + green = sensor)
6 wire ribbon = loconet or Xpressnet
8 wire ribbon = inter board connector.
Each of the 4 boards took around 90 minutes to wire up. The bulk of the time was spend gluing down the little tie down anchors as their sticky pads won't hold on to the Styrofoam very well, so each one gets a tiny dollop of Gorilla glue.
Wiring done and tested. Now to play trains for a bit and get the new (hand me down used) laptop up and running with JMRI. The plan is to have the turnouts operated from the laptop so that anyone operating only has to click on the mimic diagram to set their route. When the module is running as a stand alone layout I'll also have WiThrottle running so that the whole layout can be operated from my phone or from a tablet.