We can bump agri in the river and caves, which should have a knock on effect in exotic materials which I assume is both plant, animal(Both of which will get bumps with better growth attributed to Zhengui, also with caves we can explore fungal options, and if there's access to the underground people we can trade with/subjugate them(The latter probably impressing Mommy of Searing Light a lot)?), and mineral. We also have a rather powerful force headed down there, that just got a bump. So I'm considerably less worried about the danger rating.
Further having high access to exotic materials means that we can pay for top of the line formations to better protect our populace in fixed locations, as well as have access to 'mortal' things in droves. With a little bit of effort we can turn things from our diplomatic level trade into luxury exotics in the rest of the duchy and increase trade in the long term.
What's the word on setting up cultivator troops? Because with high exotic materials we could set up a minor/lesser sect thingie right quick. Effectively dropping high danger rating more by giving us forces to go punch rowdy spirits in the face.
That's my take. River and caves, ladies and gents. We'd have more options than moar farming (Rivers and caves + Zhengui + exotic materials = magic hot springs?) or moar mines for fief development, and the farming is good enough that Zhengui would have a tangible impact across multiple types of agriculture. Intra-trade between the group should actually be better because we'll have access to rivers (And we can build canals like good SV questers) for goods transportation to GG and CXR. Exotic materials gives us options to trade to established clans and for cultivation advancement, things like powerful formations to make home a safe relaxing place or strong artifacts to smack people with. Medium trade with the rest of civilization means that we aren't ever to likely be cut off. Then high danger = high rewards. Make those dangerous spirits pills if they don't behave.