Thanks for all the great advice. A few comments to questions...

- written expression is around organizing your thoughts and getting them down on paper. Ask him to tell you about anything or make up a story, and he can verbally go on at length. If he needs to put it down on paper, it is a big struggle to get the words together on top of the struggle to handwrite.
- we have been working on typing this summer, and he is making good progress. It will still be awhile before he can be proficient, but he much prefers typing over handwriting. When he is able to type versus handwrite, it is much easier for him in all aspects.
- the karate program he is doing is FANTASTIC in that the teacher is very encouraging and does what it takes to connect with each child.
- he does love to be on the playground climbing, sliding, swinging. This summer he has become much more comfortable on a bike, and we have been trying to ride as much as we can. Luckily we are in a town where we can ride a lot.

When the weather is nice, he probably has some sort of outdoor time everyday that involves playstructures, riding a bike or scooter. But when the weather is cold (which it is here a long time), I don't know how to get in that same level of activity. The indoor movement activities aren't as fun for him, and I don't want to turn it into "you need to do these because you need to get stronger." He is very sensitive and would have a hard time with that. He isn't motivated by reward systems, either. I am happy to do the exercises with him to make it a family thing, and when it is new he would probably join in. But after some time, I think he will just resist.

For gross motor / core, how much time per week do we need to devote to this to really make progress? How do I know if he is making progress and getting stronger?