Sorry not going to the Castle.
Say what? What could be better? Instead, it's a cave! (hence: dark canyoning)
Saturday: Walk into monolith valley, then explore cave.
Sunday: Explore one of the nearby peaks (e.g. Nibelung?)
As the cave involves rope-work you will need to be comfortable and fast on rope. There will also be a fair bit of scrambling and carrying heavy stuff around.
Marked as hard difficult due to the exploratory nature of the trip.