You are right. We are talking about deep simulation. the game’s current simulation is pretty simple. 1 person wants to travel from point A (allways his/her home) to point B (work) or point C (commercial buildings) and back, but never from B to C as far as i know. The maximum travel time they are willing to do are 20 min. . All people are simulated that way, cargo is kinda the same way. When you want to change that, you need to think about balance more carfully.
You can change the location of those points to be: workplace is the coal mine, but to actually get the mine going and get some goods you need you workers do go there. then building the acutal production chain. For every factory, this would be a hugh network, especially for the largest maps.
I like the idea about the amusement park and other landmarks.
To make this possible, we would need to change point B and C to change some times. Or maybe add onther point D for freetime activity.