I have a really large mistlands area that I've been exploring. It's one of the biggest biome areas I've found short of the starting island. But it's all tiny uprisings surrounded by waterways. A real pain to navigate.
I'd say the terrain in the mistlands is a much bigger hassle than the actual mist.

On the up side, it's given me a reason to use a raft again. That's how I've been navigating through all those tiny waterways, because the longship is way too large for the task.