Is that always the Saturday before Thanksgiving or the 4th Saturday of November? We are generally in DSM for Thanksgiving...If your son is 12 by November 23rd you guys should do the Living History Farms Cross Country race. It’s a 10k but you go through creeks and mud and fields.
At one point it was the largest cross country race in the United States. I like it because it’s a good mix of “off road” cross country without any of the wall climbing or boulder rolling stuff you see in those cross fit / spartan race things.