Once again, thanks for the input.
I had a coworker who is a former diesel mechanic check out the battery / starting issue.
After a good bit of investigating, we found that one of the black / ground wires was actually a red / positive line.
We checked the current at several points, traced the lines, connected and tested repeatedly.
Finally, once we were sure we connected the terminals and turned the key.
Now, it did not fire up immediately.
It has been about 10 days since it last ran and with the average temp being roughly 20 degrees it was not a surprise it didn't start.
I plugged in the block heater and returned later to try again.
On the third attempt it rattled, chugged and fired up.
I idled it for several minutes waiting for a friend to follow me to the mechanic.
It is now parked and awaiting its first full service under my ownership.
I am sure, I will need an oil change, filters of all types, hose leads tied off, and additional coolant given the amount removed with the cab heater removal.
We will see what else needs to be addressed and how much.
I am relieved it is up, running and at the garage waiting for a professional to check it over top to bottom.
Thanks for the help.
D.L. Jones III