You're not doing this in a weekend, year, or decade, by yourself.
I'm still trying to figure out how to unwind the mess with California. I've just been hit with this warning (after trying to log in, being forced to change my password, and attempting to find the landing page):
You are about to leave the EDD's Employer Services Online website and will be taken to the EDD's Employer Services Online web page. The Employer Services Online web page will open in a new tab.
Sorry if the tone of that sounds rude, I don’t know how to better word it, but from a US perspective, our taxes are way too broken for a 48-hour sprint to solve
To be fair, though, I think my situation was the single worst possible pairing for multi-state tax situations.