Well, I got the improvements to load in after I realized you need to create and place a rural district first. Unfortunately somethings are still broken and some new things are now broken. The improvements are no longer being counted towards the city, so I have to find out what happened there and fix that. After reading a lot more of the code and looking through error messages and what not, I'm still on the fence if this is even possible. Graphically I think everything will be able to work along with the UI. However, the actual turn mechanics and yield generations + resources and their effects might be impossible to add on to cities. I haven't seen anything in the code that would allow me to edit a specific object. Since I can't find a public function that deals with resource or economy (only getter functions) I don't really see a path forward but I'll keep thinking on it.