I've made a preliminary route for this. It's definitely not perfect, but if anyone wants to run it then that would be cool. I think it's around the length of a YW2 run. The only real issue with this is the RNG surrounding the Oni. I don't even know if Gargaros is possible in Ch4, honestly. Maybe if you route in passwords and whatnot, it'll become more feasible.

https://pastebin.com/LiqtTAPD