I think I have the soundtracks set up the way you suggest. The 1941 version is on the "L" portion of the audio board of the editor, while the 1982 version is on the "R" portion of the audio board of the editor. They are hard and soft edited to each other in Sony Vegas Pro 10 (the editor I'm using...)

I'll have to learn how to synchronize the audio for the Deems Taylor portions - there's a few places where he gets out of sync with himself (or drops narration in the case of the narration sourced from the '91 VHS).

Thanks for the feedback!