To be quite frank, the school system isn't that great for NTs either. And speaking from experience, it's the places where NTs don't do well, and aren't really encouraged academically, that have been hard for me. A school that really, really worked for NTs would work decently for us.
I don't like the idea of making it residential. You risk turning the place into an institution.
It has to be flexible, which would be a huge benefit to NTs as well. It has to present subjects in such a way that the students can learn it, and it has to recognize when someone can't grasp a particular concept and stop wasting time, and also recognize when someone could benefit from more intensive tutoring. It has to offer alternative approaches and not be dogmatic about doing something a particular way. It has to make the subjects interesting, and it would benefit from not having a fixed syllabus (but as the law requires a certain amount of rigidity and does not allow a school to be too good, this is really too much to hope for). Further, arbitrary requirements for having completed certain courses before taking others should be done away with because the prerequisite skills might be totally different for someone who does it in a different way.
Classes in nontraditional subjects would be nice, too. Also, the environment has to be sensory-friendly to the students, but that means vastly different things to different people, so it may be impossible.
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I'm using a non-verbal right now. I wish you could see it. --dyingofpoetry
NOT A DOCTOR