I've made a "SS2 Simulator" web tool to help plan and keep track of costs & resource production per settlement and caravan network. It's a personal project but I'd call it a good "beta" version if it helps anyone else, and I could use documentation help with HQ and Chapter 3 elements.
https://ss2-simulator.vercel.app/
I built this as a side project to keep my web dev skills sharp and because, for the first time in many playthroughs of SS2, I enabled upkeep costs and suddenly my whole settlement network went hard negative on caps and scrap. It was alarming as I hadn't realized how much I was playing easy mode before, so I got inspiration to build something to help me plan out a sustainable settlement network. It's not a perfect tool yet and there are still a lot of features I want to implement, but it's at a point that I wanted to share in case it helps anyone else.
For now there is no help/tutorial because it should be self explanatory for anyone already familiar with SS2, but please let me know if anything is unclear.
The plots data used to calculate production and upkeep costs comes from spreadsheets available in the SS2 wiki, but I'm not sure they're up to date and I haven't found data on Chapter 3 plots. There are also some data issues I haven't been able to figure out, such as the Cleanliness ratings being very off compared to how the same set up reflects in game.
Also, as far as I'm aware, there isn't any data on HQ costs or Chapter 3 specific plot production and upkeep values. If anyone knows differently, please correct me and point me in the right direction. Because I can't account for these things yet, this simulator effectively works up until Chapter 2. However it should still allow you to play around and plan a settlement network with enough surplus for Chapter 2 & 3 things.
I'm eager for feedback to know if this kind of thing is useful to anyone else, and what other features you'd like to see that aren't in yet if so.