You can watch all of season 1 on Netflix, Season 2 is the one currently being aired on Discovery after Parker's Trail but you can also watch season 3 on daily motion and season 4 on regular YouTube. Takes a little searching around but it's worth it. They are premiering Season 5 Apr 30th in Aus and NZ. Hoping someone posts them so they can be watched before they are taken down. Or better yet run that series on Discovery USA