So I’ve been reading about a few people having trouble accessing and/or downloading music for multiple songs off YT for listening (later) on various devices. Many browsers (Firefox, Chrome, etc) have extensions or addons which can be used to accomplish this feat. If you are a fan of live music or mashups, these are excellent tools to use to transfer to USB or device.
Firefox offers downloadhelper (and other extensions), which allow you to download in audio format. Of course, you can use this tool to download full podcasts, or any sort of audio also.
Recently, I downloaded this old school mashup.