Sandpoint is probably the most iconic setting in Pathfinder for me. I think it is by far the most fleshed out in terms of information and gaming material. It's in the comics, the Beginner Box, multiple APs...and I want to drop it into the Stolen Lands. Considering the whole of the Sandpoint Hinterlands map fits inside a single hex with room to spare, this should be easy.
My current plans are to replace Nivakta's Crossing with a slightly altered version of Kassen from CotE, and replace Fort Serenko with Sandpoint (with a lowered population). The character's earliest adventures will take place in these two towns, eventually earning enough notoriety to be noticed in Restov and receive the bandit charter.
As the campaign progresses, Sandpoint, being on the frontier and always somewhat independent minded, might declare for the PCs kingdom, especially if the PCs open up the Shrike for trade. Depending on the relations with Restov and Breovy's Noble Houses, this should play into the GoT political theater either in the background or otherwise, if the PCs take an active role.
By adding in the various goblin tribes and the cult of Lamashtu (as well as the extra kobolds from the Darkmoon Vale series) to the north, there will of course be interactions with Monster Kingdom in RRR. I'm looking to strike a balance here, not overwhelming the PCs kingdom on two fronts during RRR. I'm planing to let the players run the We Be Goblins series as a break in between sessions, hopefully endearing them to certain goblins they'll meet as NPCs (meta, i know, but it'll be fun). I'll be combining the WBG goblins with Fatmouth's tribe from the Beginner Box. This should allow the PCs the chance to ally with at least one goblin tribe and one kobold tribe, and maybe even a fledgling boggard tribe, before Monster Kingdom kicks off. Of course, I'll need to write for the other option of the PCs missing plot hooks to rid themselves of the cult threat before RRR kicks off, or they'll be screwed.
More to follow as I flesh this out. Any thoughts or ideas are welcome.