That ended up being less painless than I feared, although there's still a lot to do yet to make it presentable.
Sadly, the document is also rather lengthy. Because I took the existing d20 rules and used them word for word as written in many places, they're overly verbose and detailed. This has driven the page count of my (admittedly, still unformatted) document to over 200 pages, which I find appalling, since I never wanted anything so lengthy.
Then again, I could always remove big chunks of it. I don't really need to reprint the combat rules, for instance, or some of the other rules that anyone who's ever played a d20 game of any kind would already know. And the spell list is a very large chunk of all that text. I could refer to it as an external list and cut well over fifty pages out on that section alone. Heck, between that and the combat chapter, that's almost half of the page count!
Then again, the whole point of striving for elegance of presentation was to have all the rules needed for play in one place, whether or not I actually "needed" them or not. And since it was just a cut and paste job, I'm thinking I'll leave them.
Anyway, yeah... I'm just gloating a tiny bit. It feels nice to have as much done as I do today, even though I still have some rather daunting tasks ahead of me to make it something truly playable.