Is there a musicologist in the house?

I could use some help (no, not money, though if you’re so inclined I will thank you sincerely). It’s clear that I’m not going to teach myself music theory over the Web in any reasonable time, and I have a music project I would dearly like to see done.

What I want is to re-score the old Mack Davis tune “Oh Lord It’s Hard To Be Humble” for brass band, J. P. Sousa version, then feed it to a synthesizer program like MuseScore and get a playable file. Possible? Reasonable? Pointers? If you think you might be able to do it, comment and I’ll contact you by email to tell you why I want it.