Source: Mike Brandt
As I checked over your listing of Michigan tracks I noticed that you're missing Northern Michigan Speedway in Elmira, MI. They are open and race from May until early September. It's a quarter-mile paved track. The track is northwest of Gaylord about 10 miles. Take M-32 west of Gaylord to Camp Ten Road. Go north about 3 miles to Huffman Lake Road. The track is just to the east of the intersection.