High Level tools for GTA-style mission style - PlayMaker? uScript?

In GTA, for example, you have play a protagonist who is assigned multiple missions - he's in a sandbox, but he has a destination to trigger the mission start - then he voluntarily engages in the missions, with $$anonymous$$nted and explicit guidance and cascading triggers.

T$$anonymous$$s is essentially what I want to do on my current project, w$$anonymous$$ch is not a game, but a simulation where the user will do somet$$anonymous$$ng similar - get on a bus, he has confrontation, only then the bus starts to drive on a path, the user chooses responses from an RPG style dialog menu perhaps - $$anonymous$$s actions will drive what happens next.

He repeats until he has resolved to scenario properly.

Its all very much a state management situation, so I am guessing PlayMaker might help - I am also looking at uScript. I did my first Unity3D project in code, but because of the iteration w$$anonymous$$ch will be required on developing t$$anonymous$$s simulation, I want to work at a $$anonymous$$gher level.

If there are any other suggestions for any parts of t$$anonymous$$s, they are greatly appreciated.