first off, let me start by saying that I really LOVE this adventure path! it's well designed, and the city/kingdom rules look to be easily expandable and well designed. kudos all around on this path guys!
However...I like to tinker. i'm sure most gamemaster type people do...and i got to thinking about what I could add to the adventure path and customize it a bit for my players. here's what I've got so far (and keep in mind these are just rough ideas and not fleshed out yet):
1. early on, (say by around level 3) the party meets Ariza, a charming and very pretty young female sorcerer of indeterminate bloodline (she says she's partly fey). perhaps she provides some timely assistance in a tough fight, or is merely a reliable source of lore and/or advice. she does her best to aid the party, making friends and helping them in their quests as best she can while trying to build a potion making business in their lands. All well and good...but 'Ariza' is a succubus (with perhaps a level or two of sorcerer). her goal is to help build up a powerbase and in a short century or so, turn an entire population to the worship of chaos and evil. of course, her mask isn't perfect, and being essentially a walking advertisment for the sins of lust and over-indulgence, she will eventually let rip with one wild party too many and might attract the attention of party clerics or paladins. perhaps she increases Economy but also unrest?
2. Encounter (location: wood hex/mountains/hills). A ruined and forgotten house/complex. formerly the home of a reclusive wizard or cleric that dabbled in magics best left alone, the home is largely decayed into a rotted ruin. However, years of experiments have left a taint upon the lands in that hex, focused on the ruins. clearing the hex and rebuilding the ruins halfs the cost of building a wizard academy. the kingdom owning the hex also case illusion/shadow spells at +1 caster level while in the hex. however, given the creepy reptuation of the hex and generally spooky atmosphere, the hex also generates 2 unrest per kingdom turn.
3. lake candelmere/ruined tower. after clearing the hex and further exploring the tower, a dedicated search finds a secret cave complex on the island (located under the tower perhaps?). the caves have been largely abandoned for decades, but they were once a place of refuge and worship for a cult dedicated to the Old Ones. What happened to the cultists is a mystery, but a dedicated search of their remaining library turns up scraps of information regarding spells related to time, distance and/or teleportation. allows eligible spell casters to learn/cast transportation magic (dimension door, teleportation and like effects) at +1 caster level. however, the month following the plundering of the library there's a rash of pregnancies in the nearest village/town controlled by the players kingdom. each of these children is born an aberrent bloodline sorcerer, generating 2 unrest for the next three kingdom turns.
Anywho, just some thoughts I've had on the matter. I'll add more as I ponder the concept(s). feel free to chime in with more ideas and/or improvements!
I have about three subplots going in my game, some based on player backstory some not.
1.) a hobgoblin tribe has set up village down in the south of the Stolen Lands. They are currently fortifying their location and sending scouts out. The PCs have come into contact with scouting parties, and they have not ended well.
2.) A were-brush thylacine oracle 9 is holed up in the Nomen Heights with her daughter. She is currently searching for a mate for her daughter so they can continue the family. I plan on kidnapping the sibling of one of the PCs and making them go save him.
3.) Ogres ravaged the village of one of my PCs, so now there is an ogre clan that will probably ravage a village they establish. The clan is headed by an ogre mage they'll have to deal with.
4.) One of the PCs owes someone a favor. I plan on having them set up shop in the gold mine hex so the players won't be able to use that resource.