As I said, I'd report back in when I got around to using the list/link/thing, that Black Falcon suggested for my problem.
I got around to using it. Rsults: Positive. Very positive. Apparently that missing backup disk has several more songs on it than I remembered.
Critique: One of the last steps is to wipe your playlists before re-upping your music. I would suggest not, since the upload moves the music into a different folder that you can access and doesn't affect your playlists.
Sadly, I wiped. Sadder still, most of my music happens to be one off stuff from the interent. If Itunes doesn't carry the song, you are now left with a lot of blank space. Since I wiped, I now have a lot of music with computer-code title names.
Other than that small hitch, would highly recommend this process/list/link/whatever.
Thank you Black Falcon and everyone else.