I have been running the Adventure Path for several months now with a group of 8 players. I have moved Cauldron to Sembia in the Forgotten Realms. I really wanted to run a more euro-centric adventure so I was forced to change some of the encounters to fit. For example, in Flood Season, I changed Tongue-eater and the baboons to a Werewolf and Dire Wolves. I also replaced the dinosaurs who were eating the carrion behind the Lucky Monkey Inn with two ghouls and one ghast. In Zenith Trajectory, I changed Garrek the mummy/torturer into a creature from the Fiend Folio, that was called something like a Quth Mara? Sorry, don't have it with me, but I would recommend that anyone who has access to the FF look it up as a skinless, undead torturer who can spit and ooze acid made for an excellent character. After my characters left the prisoner's in place during the adventure, they came back to find one dead, and the other one skinned and propped up to make them think the torturer they had killed had returned. The thing I have enjoyed about the adventure path is that, even though several of the players I DM for have been playing since the mid-seventies, they are not familiar with the unusual creatures introduced in the AP. These players are still scratching their heads in wonder about what that creature was.
Dave