I finished up the dash today, fixed it to the chassis and plugged everything into the main harness:
Here is a view behind the dash:
This is what it looks like from the driver's point of view:
The reverse dials look awesome! Here are the switches and lights explained:
And under the dash, where the gauge selector/programming switch and 5volt USB charger are located:
I did a quick continuity test at the battery to see if anything was shorted, but looks good so far. Tomorrow I'll hookup the lights and sending units, then the battery to see if everything works as intended.