Can you get an OT eval through the school? DS4.11 will be getting OT for writing from the school therapist. He has regular (private) OT for sensory issues and while his therapist is great and does do writing skills with other kids, she didn't find him be very much behind yet the school did! Which is strange because from what I've seen, school is usually the last one to jump in but in case of writing, they are willing to help right from the start.
As for Children's hospitals, I can see how they are great for kids with more complicated issues but when we went there for an Autism eval with the older son the only person we got to work with was an intern and now we're back at the beginning, looking for more answers, this time going through the University of Chicago, since they do a lot of research on Autism. But now I'm side tracking ... just wanted to give my opinion of going to Children's for something less severe.