Is there a reason we can't just leave this area open permanently now that they've gotten rid of the turn-in-to-open mechanic? Just get rid of all the special chests and stuff with monsters and keep this area open like they do with the challenges.
In fact, maybe just get rid of everything except the actual challenge and just plop the quest opening in 3bc. If you can pick up all the ingredients in the quest any way, no real reason not to just let people run it all the time. Would just need to remove the compass-to-open thing, but that shouldn't be impossible.
(Note: I like the winter festival and halloween thing as stand alone events, although I hate that the halloween things decay--lame.)