She could, as Carmel is on 176, but 41 is just so far east of Carmel by the time you get to 176, it still does not make sense as a route, IMHO. She would drive under 94 heading to the school! The only benefit of that route to me would be avoiding the Waukegan toll plaza, but she would lose that money in distance travelled. Maybe that route was just simpler to her, with fewer roads and turns. But, 94 to 21 is just faster and is the preferred route in Google Maps. 41 has stoplights at various points, 94 has none, and she would have been on 94 all the way to Illinois. Why get off of it and onto 41 less than 10 miles from the preferred route 21 exit? Maybe she wanted to stop somewhere en route.
I had not investigated the driveway at all, but there are some hidden driveways along 41 in that area between Stearns School Road and Wadsworth Road. I see two just north of Stearns on the west side of 41 on Google Maps. Not sure if it was one of those.