Possibly placing the beginning in Kaer Maga. Seems like the setting however may not be the problem but the bosses themselves. Anyone care to share their thoughts on this?
I'm just curious, with all these other APs, why choose Shackled City?
It was the first AP, and as such, devs didn't have many experience in making them as they do now, and it shows in some parts.
It's also had the most playtesting and community content generated of all the paths. Not to mention Life's Bazaar is possibly the best introductory module ever for a campaign.
There have been a couple other threads about putting SCAP in Golarion.
The AP can be run in Golarion, no problem, but I'd think twice about Kaer Maga. You would have to change so much (History of Kaer Maga, Crate sea of the shackled city, outskirts of the city etc
Spoiler:
There is also the fact that the campaign would bring destruction to Kaer Maga/Cauldron greater than the age of darkness did, which is hard to pull off
.) to make it fit that you will be more or less left with a name.
I'd advice you to use the Shackled City as it is and put her somewhere in the shackles or maybe northern Mwangi. Cauldron is one of the coolest aspects of the AP, so exchanging it for another cool thing (Kaer Maga) or replacing that other cool thing wit Cauldron seems like such a waste ;-)
Anyway, there are already some cool threads that might help you, most of them linked from this one.
Most of the module should be able to fit into Golarion well enough, I think. I suppose you'd have to consider whether you want to add Carceri and demodands to the Golarion cosmology, or whether you wanted to translate them into something else that already exists.
I set mine on an Isle in the Shackles. Made Sasserine into Port Peril and it worked out fine. It's pretty contained unless you choose to do side treks, which I did. In the quest for Alek, I had them appear in the desert near Osiron. We played the Styes as a side trek, which I placed on another island, and was going to run them through Scuttlecove, but did not due to time constraints...It worked very well..