The bulk of this thread is over 2 years old, but here is my current work flow for this sort of thing. There were two parts to the OP. One was to hear the rhythms of a piece of music, the other was to get a PDF to become editable notation in Musescore.
The following is only for clear, printed, scores (not hand written)
My music is on an iPad using the app forScore. I can 'share' the PDF from forScore (or from any app or email) to open in another app - PlayScore2. Once opened in Playscore2 you can play the music with a variety of instrument voices, and change the output key up or down. It is not 100% accurate, and misses some things, but if just wanting to hear a rhythm, it will be fine as long as the section is read properly.
From Playscore2 you can save the score as MusicXML file and airdrop to your Mac, or email the file to yourself to the computer. This file can be opened in Musescore. In Musescore it is easy to tidy up any misreads by the optical character recognition, and of course edit it as you wish.
I have been using this recently to create clarinet quartets from sax quartet parts, transposing Eb / Bb switches (Bb sop sax to Eb sop clarinet; Eb alto to Bb 2nd clarinet; Bb tenor to Eb alto clarinet and Ed bari to Bb bass)
Chris
forScore
forscore.co
Playscore2
PlayScore 2 takes traditional music scanning to the next level. Using the latest techniques in Optical Music Recognition (OCR for music).
www.playscore.co
Musescore
Create, play back and print beautiful sheet music with free and easy to use music notation software MuseScore Studio. For Windows, Mac and Linux.
musescore.org