I would stick with the NFHS books. These are "rule books", "case book", "simplified & isllustrated", and "officials manual"
These four books will be your bible, so to speak. Now, get games and more games. There are probably some training classes in your area/state. Find a mentor, and get rolling. I assume you a smart guy (because of your well written post, not your profession
).
Good luck, this is really fun (and hard work too).