An update....some frustration today.
Worked out a route for my battery cable (which I don't yet have) from its location in the trunk, left side. By far the easiest route forward required the cable entering through the rear bulkhead (ie the panel behind the seats) and then going down through the tunnel. I checked thoughly - I thought, but not thoroughly enough - that I could safely drill and tap holes for attaching a cover over the cable. The drill broke passed through the panel ....because it hit something. The "something" was a tee connection for the rear brakes.
So, needed to check out if there was damage. Not a 5 minute job; had forgotten the accessibility issues in that area. I had to pry the junction out somewhat to access a view behind it....
As it turned out, after some investigation with a medical mirror, all is OK
Cheers!
Glen