Ever considered the migration assistant that comes with OS X and fires up the first time you use the MacBook?
Specifically, use it to transfer the home folder ("user account" or whatever it's called). It will get her iTunes music, as well as any other stuff in her home directory (backgrounds, dock preferences, etc). Takes about 45 minutes for that much music, and then you're laughing.
Seriously, it's great. You can run it manually if you opted out initially, though it may crud up some stuff on the new machine if it runs into conflicts.