Thanks for your praise and feedback.
I'll update the typos you highlighted.
Your point about the New World line is interesting. I'll have to give it some thought.
The green/blue hydrogen notion hadn't occurred to me. For now, I think it's best to assume any society willing to re-wild the Great Plains is going to use green hydrogen.
I'm hesitant to add to many extra twists and details, as I don't want to fill up the page too much (though I do like your suggestions). I have given some thought to writing a supplement and may add details then.