Thanks for the information everyone.
The school has around a hundred kids. Two classes of preschool, one K and one 1-6. The preschool and K can be full or half day. I am thinking a half day (less than 3 hours) would be best for him.
I also just learned there is a science, tech., engineering and math magnet in a neighboring school district with mixed age classes that we might try for next year. Apparently, if there is room, out of district kids can go.
He goes to a mixed age art class that he'll be able to continue once school starts. His opinion of the class changes with the subject. With the Chinese Dragon, he tried hard to make it look good BUT with the portrait of a Japanese woman, he decided she should actually be a zombie lady with flaming red eyes, green skin and brains coming out of her mouth. Not exactly what the teacher had in mind.