Thanks for the advice guys. I ended up getting a little lucky that the party had rescued one of the goldfish people, and I made it up that he was actually a spy from the veils of pride who was caught in the trap when attempting to learn more about Karzoug's hibernation method. His knowledge of ancient Xin combined with Brodert's lore and a visit to the pathfinder society were enough for me to make a plausible explanation for tracking down the city's true location. This cut the cabin adventure entirely.
Now the party is looking down on the city, ready to make their assault. Since time is soooo tight now, I plan to update the occlusion field with the change that anyone wielding a dominant weapon against greed has the same immunity as a sihedron ring. There will also be many plot hints given that the return of the runelord is coming basically "any minute now" and that the party needs to rush up the mountain to start the assault on the spire. I feel bad gutting so much content, but you gotta do what you gotta do, and I want to leave enough time to the final assault is a bit drawn out and memorable.