Well, I sure wish I could find a place to write up a bug report to Google about this lost music thing.
With 2/3 of my music loaded but not registering as "there" by any music program (including Google Music Player), I wiped the music folder and marked ALL of my online music for "offline" listening.
4GBs later, all my music was on the phone. Ya think Google put it in the Music folder? HECK NO! It's still empty! In fact, I can't find that music ANYWHERE!
So this is a major ICS issue, with it losing my music like that. Rant over.
Oh, by the way:
Astro File Manager can see the SYSTEM FILES on my Nexus and I'm not rooted!