Tracking the Loot
I just cannot figure out a logical reason why they would take the Greenest loot all the past the sword mountains. They have a hidden flying castle which makes better time than any oxcart and doesn't involve hiding important resources from multiple city customs. Dead Mire isn't even the fastest way to get to the Well from Greenest.
I'm planning to have the castle land outside the hatchery camp, and then have them track the castle and rezmir up the trade way from Greenest as skyreach stops at various rural areas to pick up loot. The castle being a carrot to bait the PCs the right way. Over a month of in game time, I cannot imagine my players not interacting with the slow carts at some point/not chafing at being told they must silently and slowly track some boxes over several leagues. I'd rather it be an investigation/man hunt touching on the ways the cult has infiltrated baldur's gate, daggerford, and waterdeep. And have them discover rezmir's castle on their own.