my youngest is not diagnosed, but we think is ASD, with defintie elements of PDA.
Her room is like this. (she's 13)
She likes it this way, and so I have tried to find a middle path.
Everything does have a place, and those places have changed to how she would like them, which helps her to organise, so her teddy pile used to be in hanger on the back of the door, but she wants to see them from her bed, so we made a pile in the corner of the room, which drives me nuts as it is basically on the floor, with the rest of the mess.
She doesn't deal with clothes at all, so I have encouraged her to have a heap on the chair, rather than spread all over the floor.
he big desk, designed for homework is constantly covered in half finished art, but she can't actually use it for art as then she would have to move the half finished stuff...
So my compromise, is, every Saturday she has to 'clear' the floor. Her definition of clear and mine are very different, but in essence, all dirty clothes in laundry, all other clothes moved to a heap, all plates and rubbish downstairs.
If enough floor is exposed, I hoover it!
It doesn't look tidy by any means, (pigsty would be better description) but it is enough for her to then function. If we don't do this, I start to get mad panic - I can't find.... during the week, and then I have to help her search.
I do insist they do their sheets, and I give them a pile of clean on a Saturday morning, and they know they won't get pizza at dinner time if sheets aren't done!