There are various meta-level questions left unanswered by textbooks, such as "how do I go about deciding which textbooks to read in a particular subject," "how do I go about deciding which subjects to study," "what resources other than textbooks are good for learning math," and "say, what's the big picture here, anyway?" The goal would not be to regurgitate the content of any particular textbook.
I also expect rationalists to be more goal-oriented than most people, so my recommendations for them would be different from my recommendations for people who just want to learn whatever math is cool and interesting. My recommendations would depend heavily on what those goals are, which is why I'd like to know what those goals are.
I hope you do write this. I'm trying to get comfortable with using math again and I'm pretty much starting from scratch with only my rusty half-forgotten high school algebra and pre calculus (I haven't even learned calculus. Should I? That's why I need your post).This kind of general guidance about what to focus on would likely be very helpful.
My goal (for now, unless I try and find out I really like some specific direction of study) is mainly just to learn whatever math gets me the most mileage in understanding the random grab bag of subjects I happen to...
If it's worth saying, but not worth its own post, even in Discussion, it goes here.