The music I've downloaded from Google Play has to be accessed separately from the music I've downloaded from my computer into the Music widget. Is there a way to combine the libraries?
Welcome to Android Central! Music downloaded directly from the Google Play Music app is intended for offline use by the Play Music app only--it can't be seen by other music apps. If you want to consolidate, you'd have to download the music from your Google Play Music library website on your computer browser, then copy those mp3 files to the phone.