User blog comment:Na299/Ways of Gold Farming/@comment-49.149.51.5-20150515091257/@comment-208.184.33.66-20150515144524

It only works, as far as I know, with the challenge events and when you win a particular event, at which point the game automatically moves you on to the next event in the challenge (with the exception of the stages that have multiple events in one grouping). There may have been more opportunities before, but they have been closing the loopholes over the various updates, so this is what is left.