gentlemanfarmer wrote:... one of the things I hope to do in the coming days is visit the music librarian at our University, and see if any of the old band/orchestra/theater club music survives from before 1930 and where it is housed, if it's still on campus....
These things tend to be kept in "Special Collections," and sometimes you need to get friendly with librarians to get access to it, or pay work-study people to photocopy it for you. Knowing what pieces you're after is, of course, very useful, so you're a step ahead there. And there are collections at a number of universities (I've got some listed at the bottom of our "About Photoplay Music" page), and if you find more, please let me know and I'll list them. I learned last fall that there's a huge collection at the University at Austin Texas, but it's uncatalogued, so it's not yet very useful.
Unlike Jacks's experiences, I find that almost all of the historical arrangements can be used as published, as long as you have piano, violin, and cello. All of the important lines are cross-cued into those instruments. I'd say that fewer than 1 in 50 of the pieces you hear on the Mont Alto orchestra scores have been re-arranged to work with our quintet of piano, violin, cello, clarinet, and trumpet; and most of those are dance pieces from the mid to late 1920s that use saxophones extensively.
For instance, on the "Ace of Spades" piece currently on our home page, the first time through the trio (at about 01:37) was originally arranged for three saxophones, so I transcribed it to violin, piano, and clarinet. Then there's a trumpet solo that sounds improvised but was written out (for the many non-jazzers in the business) note for note in the arrangement, then a trombone "solo" that I gave to our cellist by simply handing him the original trombone part. Everything else is straight off the original score.
Make sure that your players know that the cue notes for missing instruments should be played, and I think you'll be fine.