I can tell you what I did, back 30+ years ago when computer curricula were not an option. I took prealgebra in 7th grade, and algebra in 8th (normal honors track at my school). Then I went to CTY the summer between 8th and 9th grade and took algebra II/trig and analytical geometry, plus tested out of regular geometry, so I was ready for calculus when I came back for 9th grade. That took some fancy footwork to talk the school into, but they did let me take calculus AB (while requiring me to do all of the end-of-chapter tests for the skipped classes - I knocked most of it out during the six weeks after the AP exam). I had to take calculus AB and calculus BC in two consecutive years, which I thought was totally ridiculous, but I then was able to take math courses at the local college during my junior and senior years of high school.
I don't really recommend this track if you can find a better way, though.
