For what it's worth, I've been downloading MIDI orchestrations off the internet, loading them in Sibelius (music software), and playing the file. You can watch the score go by, play along with it, isolate the bass part, etc. And the best part is it is free. (The midi files, that is). Finale probably does this as well. You can dl free versions of that, though they are limited. Anybody know of any other software that can do this?
Do a google search. This collection is particularly rich:
http://www.classicalarchives.com/notes.html
It isn't perfect, the sounds are a bit mechanical, much of the expression is missing, but it's another learning aid, and can be good if you really can't find anything else.