I have been keeping the momentum in the push to finish this project. Over the weekend got quite a bit accomplished.
The wiring is finished.

Under car batteries are in place.

I hooked up the gauges, for now I just have voltage, current and brake vacuum (I had a spare boost gauge lying around). This is just a temporary mounting of the gauges and plan to get something more elegant.
Today I finished hooking up all the batteries and did the first voltage check.
The only issue right now is I seem to have a high voltage short to vehicle ground somewhere. I need to track that down before turning anything on.