Copy arrived today but without Dusk. Have contacted FFG so should get the missing card soon.
From a quick browse it looks like a very tough Quest which plays a lot of tricks with your Willpower, and with the Spectral and Battle keywords appearing at some stage you will really need to think hard about the stats of your characters. It looks doable because 1B and 2B do not require an awful lot of progress to complete; 3B on the other hand...
All this without having actually played it, of course.
You can play it since dusk is essentially the same card as eventide, since after you place the 4th progress token before switching to midnight. When you will just have to remember that you switched from eventide to dusk since encounter cards will start to be buffed while it is in play.
In terms of difficulty it's a pretty easy nut to crack, and was winning consistently with a few different decks on my 2nd day of owning it, but it is still a fun quest, and one that will see the table often.
I think Glaurung's Thorin & Company will crush it, since willpower and attack stats are the key to victory in this scenario. This usually is not a problem if Dain is in play, but I am curious to hear how it goes with this deck. I would resist the urge to play them right away, and give something else a shot first.