I've been homeschooling our Kindergartner for little over 2 months now and have been having similar problems. He's also 2E ... BAD SPD and like you said "questionable" in our case PDD-NOS. Plus because his cold allergy also seems to affect his behavior. We've had days when we couldn't get anything accomplished at all and then we tried doing some stuff while he was in a trampoline (it's one of those 5 foot wide with enclosure that can be indoors up to 100lbs) and it's amazing! He can't tell me what 2 + 2 is when he's sitting at a desk but he'll easily tell me what's 22 + 6 while he's jumping in the trampoline. When he's not jumping, he's just sitting in there enclosed from the outside work listening to ebooks on the iPad or doing all kinds of other activities on iPad as well or watching nature and technical shows on my computer screen. It's amazing what having him sit in that bouncy enclosed space does for him! The only thing he has to do outside is little bit of writing but I'm not pushing him too hard because he's just not ready for much more and arts but he loves doing all kinds of little artsy projects. I'm happier when he spends 30 minutes cutting with scissors than if he spent 5 minutes suffering through writing practice at this point.
So,enclosed indoor trampoline did the trick for us
