I would try the Vendetta demo. It is set up to be like an axle with spokes for questlines and have random scenes, some repeatable, some one-time and so forth. Programming is my weakness but what @Vendetta describes in his WiP thread sounds like he has done this and more.
Here is the link to his thread:
Edit - Also, welcome to the community. There are a lot of good people here and I hope you find a home here as others have.