Running Man of Tech: Can the Apple Watch 2 actually last a marathon?

I'm on the train heading up to to the north of England, where I'm racing the Chester Marathon tomorrow.I'm desperately trying to work out how to copy Apple Music playlists from Spotify - turns out there's no way to easily duplicate across platforms without paying money to use random desktop apps.The reason for this is I want to imbue my Apple Watch 2 with enough music to power me around the marathon tomorrow, where I'll be properly testing it over 26.2 miles.'Properly' is the key thing here. I'v