I just randomly picked some open quests in the Hinterlands and went with my party to cross those off my list. I'm level 5 currently, and suddenly faced a level 8 mercenary leader. That one easily wiped the floor with my party, so I reconsidered my quest choice.
That second choice turned out to be a mistake as well, I actually managed to kill two level 12 enemies reasonably quickly, but then I noticed that this encounter was a rift and all the other enemies far above my own level spawned and wiped my party again.
I had assumed that the areas were roughly equal in level, but it seems that I was severely mistaken in that assumption. So now I'm wondering how I can quickly find out the approximate level of a quest or area? Preferably without killing my entire party in the attempt.