I won't vote since I only have werewolf tunnels and Mt. Komorebi in my game, not the others...
The werewolf tunnels involve almost no stress at all and no gameplay challenges, but there is the possibility of getting in a fight, or even getting turned into a werewolf. (This is apparently unusual, but it did happen to my very first sim to ever explore the tunnels, Salim Benali's daughter Laila from my San Myshuno game.)
Mt. Komorebi there is one point where you wonder if they will survive or not! (the tallest ice cliff)
It was fun and suspenseful.
But needs are very easy to take care of. There are tons of warnings and suggestions about bringing your own supplies, and then there are multiple places to sleep etc. along the route. And there's no way to get lost or anything so there is not much challenge in that sense.
https://forums.thesims.com/en_US/discussion/comment/18343965/#Comment_18343965
