Looking to point iTunes (playlists and all) to a new location

Question

Hello all,
I'm in a bit of a pickle of my own making, and I greatly appreciate any help anyone is able to offer on this one.
I've been using iTunes as a playlist jukebox much more than as a file organizer. Here is my normal mode and sequence of operation, largely because I came into using iTunes later than some other programs out there (like MusicMatch Jukebox or WMP).
1. Rip tracks to my hard drive using another program.
2. Add folders/files to iTunes, then create playlists, usually one CD=one playlist. If I have a multi-CD set, I will create a playlist of all the CDs together, instead of individual playlists for each CD.
3. I do not have iTunes organizing files for me, and I do not create files when adding to the library, because they are already created on my hard drive.
Several months ago, my 80GB internal drive was running out of room, so I copied everything to a 100GB external drive and started ripping newer tracks out there as I acquired them, and creating new playlists for those newer tracks. I did not re-organize my iTunes library at that time, because I didn't know what to do to accomplish that. So, my current iTunes library has older playlists pointing to files still on my C: drive and newer ones (after the copy to the external drive) to my external drive.
I also have some music that was imported directly into iTunes, mostly acquisitions from the Music Store. Those files reside exclusively on my C: drive, no copies out on the external drive at this time, and if need be, they could stay on C:, but if I can also move them to the external drive and iTunes can still find them, that would be great.
I would like to retain all my playlists that are currently referencing files on C:, but still point iTunes to the external drive for every file and playlist reference, since copies of the files on older C: drive playlists are now on the external drive, except for the directly imported files already mentioned. And, if you didn't see this one coming, I'd really like to reclaim the music file space on my C: drive, only after iTunes doesn't look there anymore for files to satisfy the playlists. Well over 50GB stands to be gained here, once reclaimed.
Now the kicker - I have over 20,400 tracks and well into the hundreds of playlists.
So there you have it - I have dual copies of most of my music files until I can get iTunes to forget about the old copies entirely, and to not have to re-create those hundreds of playlists to reference files on the external drive.
I have thought about using an editor on my iTunes library XML file to change all references to C: to my external drive name (and top-level folder references to change as well), but no editor (XML or otherwise) I have in my arsenal will hold a file this big.
Again, many thanks in advance to anyone(s) of you kind readers who might be able to throw this old (53 YO) dog a bone of useful information.
With a little bit of hope and a whole lot of thanks,
Gorgo
Cincinnati OH
Dell Dimension 2400   Windows XP   External hard drives

Answer 1

Once more, thanks for responding, Mimico!
Bad news here, I'm afraid.
The consolidation aborted because apparently a file name was too long for the copy, and there was only a puny generic message box notifying me of samesaid abort. No reference to what track(s) caused the problem. I could be all day chasing that one down. No can do.
Needless to say, I went back to the original library file on my C: drive. Then desperation set in. I felt I had no alternative but to delete 99 3/4% of my library entries manually, leaving only those tracks that I purchased through the iTunes Store. The plan being, to also kill all existing playlists and rely on the Browser instead, once I got my track references lined up, supposedly by the following step.
Then I did an import, pointing to the master folder on my external drive, thinking it would pick up everything underneath, per the directions in the Help file for mass imports of music.
The import managed to pick up only about 1/7 of my collection on the external drive, even though it is all there on that drive under that folder. There may be different layers of subfolders and files under the main folder, but the predominating structure is an artist subfolder, than a CD subfolder, then the associated MP3 track files at the lowest level. Some of those CDs with that structure got picked up, many others did not. Bad result.
Is there any alternative to manually searching for missed folders and importing them one folder at a time? That would be the biggest help to me at this stage, I'm afraid. Otherwise, I guess I have to do what needs to be done.
Sitting in my doghouse,
Gorgo