I don't know if Summit has a middle school, but it does have a HS in Rockland, maybe in Nyack (I think) which is residential. My friend's daughter went there after having big issues in district (on LI) and she is now an honors grad of NYU. I believe she went there after 9th grade and her issues at the time included drugs and drinking, sex and wild ODD. She is now a straight arrow vegan and someone I would be thrilled to have my own teenaged daughter turn out like. She credits Summit (and her parents' insistence that the SD step up to the plate and help pay).
Also, check the NYS Education Dept. website for approved schools. That's how I found the school in the city that my dyslexic child now attends at SD cost.
There is also a residential school upstate but I think you have to be 15 or in HS to go. Another friend's son actually earned his Eagle Scout badge there and he had issues similar to the girl above, but his included some minor arrests and fights at school as well. Last I heard, he was working and thinking about community college.
Good luck.