I like this idea. I remember doing this in FFXII. Took a wrong turn in the stupid sandsea and ended up in the Zertinan Caverns. Panicked when I saw the mobs were twice my level, then went on a suicide run out of curiosity of what was in there and found Adrammelech.

I was expecting the beastman strongholds to be similar, but they're neither scary nor exciting.