I have an idea for a game like theme park but don't know how simulation games are made.

I am not some noob on his first game so I appreciated constructive answers instead of "its hard, don't do it".

What I want is to know how simulation game mechanics are put together. I figure it would be heaver on the AI than normal games and not knowing much about AI would like to know some programming techniques I should look into for this style game. specific techniques please not just a book on ai.

what sort of architecture would be used? I guess it would have some sort of probability engine with pre designed events that are triggered based on the AI state.

Would it use a FSM or be purely event driven ?

Any information on how a sims game functions would be cool.