Homeschoolers: If money weren't an issue....

[mrs.b]

You can give Time4Learning a chance. They now have up through high school, and it's entirely online. You might need to supplement with additional resources (we definitely have), but it sounds like it might be up her alley. It's only $20/mo. to give it a shot and see how it works, and they offer all the classes, a full curriculum (again, we had to supplement).

A few notes:
My son is also Autism/formerly Aspergers and now homeschooled for the same reasons as well. He has some sound sensitivities, and some of the Time4Learning lessons have animation where the sound can be sharp and sudden. He does NOT like this. That might just be for the younger grades/lessons, though, so you might not run into that.

While my kiddo is also very good with computer-based systems and we thought that was ideal - and he does do fine with them - he does so much better with teacher(parent)-driven courses. We've fallen in LOVE with the curriculum options from Pandia Press. Coincidentally, they only offer Science and History! It's experiment-based (learn by doing) for science, and we did not use them for history last year but are for next year (I already have the books) and it looks just as direct, to the point, and clearly drafted. There are not a lot of flashy images or distractions in the published format. The history options go up through high school, but they have not yet published all the science books. If you are open to text-based options, I've also developed a fondness for the Saxon Homeschool products (published by Houghton Mifflin Harcourt). We've using their Grammar & Writing program next year, and I already have the texts and know he's going to do so well with it.

I've heard good things about K-12 which is entirely online, but it's not available in my state so I did not research it too far. If you're open to religion-based curriculums, I've also heard very good things about Abeka's online academy, but cannot say how either of them would coordinate with your step-DD's special needs. For that reason, we've steered away from anything like those. Maybe when he's older and a bit more independent.