chucky1973 If you go over the 30 days without 'calling home to Spotify' then your playlists will not be able to be played. I highlighted this because you stated that you would be away for a few weeks. :)
Up to three devices offline. Wifi is only needed once every 30 days!
There is also a 30 day free trial for Premium.
https://www.spotify.com/uk/freetrial/?_ga=1.201096046.1518482586.1401806859