Feeding larger conduits for wiring access to the battery compartment, I used a hole saw to cut a 1 ½ inch hole into the floor at the driver side pillar (widening the original wiring conduit) and then cut a nasty 1 ½ inch hole through the front side wall of the battery compartment. After considering using an angular grinder to cut a rectangular hole in the front side wall to install PVC box, I decided just to line the hole with Eternabond tape. Not very elegant but functional.
I pulled all the upgraded wiring into the battery compartment.
Ran some ground wire from the above-cabin cabinet down to the chassis for the ham radio and antenna tuner.
Inspected all of the ground connections at the chassis (near the battery compartment, near the black tank, near the generator) and noted that they are all appear corroded and covered in rust.