Thanks, TS-Russell & paulvha,
The problem has been resolved (whew!).
With
Hardware and code from SparkFun,
The IDE from Arduino
and
The Library from RadioLib,
it seemed good to seek insight from others too.
My issues came down to managing a project under Arduino.
Renaming a project (sketch) requires the main .ino file to have the same name as the folder. Moving it around triggers a massive tar file download and the opening (and inclusion) of all files in RadioLib.
I saw something similar in an IDE from ATMEL, and though the overhead looked strange, I figured it would take care of itself.
In attempting to accurately describe all my steps for correspondents like you, I replicated my experience, this time staying in one folder with one project name. well, there is no trouble now. With prior downloading of the RadioLib file, it looks like I’m OK now. Everything works.
Only 1 file is open in the IDE now, the .ino, and the compiler only pulls-in what it needs.
A TypeDef.h file needed slight editing, as it has been modified from a prior version, which was in-view at the time of the main source code.
Regarding this file which troubled me …
<module_name>.h
You will see right-hand arrow bracket is located to the left of the filetype extension.
This is not a call to a library file.
It appears this way in other places of the code, so it is not a typo either.
It was a module name assertion, made somewhere in the labyrinth of supporting files, but no longer an issue.
sincerest thanks,
Michael B