Yeah an Apple Watch with LTE. Not sure if LTE is required, but needed for streaming. Could probably store data on watch before heading out. Need Bluetooth headphones. Battery life is ok.
LTE is not required. I use my non-cellular Apple Watch on runs and listen to either music or audiobooks. You sync your Apple Music music to the watch via the iPhone's Watch app. Audiobooks are similar, but since most of mine were from Audible I use their app to sync to the watch.