First off, you're a kickass parent, that's an awesome thing to do for your daughter. How easy is it to sync with music she wants to listen to? I haven't touched Rockbox in quite a while, but I imagine it's still expecting DRM-free audio files of some sort right? Other than bandcamp I can't think of any good source for finding some beyond ripping audio streams and organizing it yourself.

I’ve been thinking about doing this too! Would love to get back to maintaining a personal music collection on a dedicated mp3 player.