Base game: which quest recommended?

By MoRRi2, in Descent: Journeys in the Dark

In a few weeks, I will have a group together for playing Descent (finally, I might add). I've played the first two quests, and I was wondering: which quest in the book is the shortest? And which one the most challenging? I would prefer to have a quest that's both short AND challenging. Maybe someone would recommend one of the downloadable quests over the ones that came with the base game?

Morri said:

In a few weeks, I will have a group together for playing Descent (finally, I might add). I've played the first two quests, and I was wondering: which quest in the book is the shortest? And which one the most challenging? I would prefer to have a quest that's both short AND challenging. Maybe someone would recommend one of the downloadable quests over the ones that came with the base game?

I have not played it, but I've heard good things about the downloadable The Chase quest.