It's not as complicated as it sounds.
Imagine that you currently have to escort your child to and from school, handing him over to his trusted adult, who gives 1:1 support at school, and hands him over to you at the end of the day and you escort him home again.
You can't imagine it being different. He is far too impulsive, far too flighty, far too vulnerable, south so little awareness of danger and routine to do anything else. But what would your aspiration for him be? In an ideal world?
Imagine that you would one day like him to be able to leave the house on his own, walk to the bus stop 3 roads away, wait while 4 different buses pass him, get the correct bus, travel on the bus, get off at the correct stop, and walk the short route with 2 road crossings to college.
So, what will he need to experience, learn and do to achieve that? He'll need to do lots of bus travel, lots of road safety training, timetable training, independence work, troubleshooting (what do you do if the bus is late, or doesn't come, etc.), Route planning.
So you do that for each area of his development.