How can I takeover a town in a Pathfinder campaign setting

[Cassy]

My group is playing RotRL and the starting town is Sandpoint, home to some corrupt nobles, a local crime family, a pious priest, and troubles that have the potential to erode the commoners' faith in their elected officials.

I want to foster that erosion of faith in their leaders so that I can become the power behind the throne. I want to start making children sick (I'm a witch with bestow curse) so their parents have to come to me for help when no one else can. I want this healing to appear mostly charitable to members of the town and at least the cleric in my party. I want this healing to put important members of the town In my debt. Think Rasputin with slightly less debauchery and a better public image.

My group is already the de facto security force for the time being as the sheriff is in away in the regional big city. I want to use the support from my clients to takeover a department of the town. The department I want to takeover first would be, wait for it, sanitation. Why sanitation? No one looks too close into the business of handling garbage and Sandpoint is having a problem with goblins raiding the local dump to gather resources so they can build armor and weapons. I want to use this threat to gain control of Sandpoint's sanitation department and to levy a new tax to secretly provide me with the means to start buying power from less savory npc's, specifically the Scarnetti crime family.

I've talked to my GM and he is totally for it but said I would have to find out how the mechanics would work, if there are any, before he would allow our party to embark on this undertaking.

Any thoughts or advice is appreciated.

[Sindenky]

There are a hand full of mechanics that come to mind, mostly stuff involving down time/kingdom building. In my experience those rules fall slightly short of hitting the mark. I would advise skimming them, then moving on.

So the best thing to do is assign factions and assets.
Factions would be anyone with their own agenda, with multiple groups making up factions. Some you have named here would be the crime family, the corrupt nobles, the non-corrupt nobles, the priest ect. Factions can work together, but if you can envision them being able to disagree at any point I suggesting making them their own group.
Next evaluate the assets. The would be departments, like sanitation, law enforcement, farming, transportation, court, tax collectors, ect. locations such as the land fill, goblin village, street turf, housing blocks, sewers, police station, prison, court house ect.
Once you have all the pieces together, lay them out on the board. Assigning each asset under a faction's control. In some cases, multiple factions may share partial control of an asset, in this case give them a %, and in the even of a dispute, either highest % wins, or oppose CHA/leadership checks with a bonus based off your controlling %.

Now you just have to take control. You can buy it out, create discord, strong arm, ect. The options are endless. I would really advise your DM read over the social conflict rules provided in ultimate intrigue. I had to read it like 15 times to fully grasp what the creators were trying to tell me, but when it hit me it immediately became one of my #1 assets as a DM in regards to campaign building.

Fun twist on things, Have assets provide bonuses to the controlling faction. A reason to fight other than the sake of fighting.