What did you do with the secrets lots in Mt. Komorebi?

You can build there once you've found them (if you have the freebuild cheat on), but you can't save until your excursion is over. I haven't built on them, but if I did, I'd probably just add a small shelter with necessities. There's not much point to anything else. Sims have to go on an excursion to reach them and you have to leave when the excursion time is up.