Dave from Kirkwood on 9/23/2019 9:11:04 PM:
There is no camping right at the Machens Trailhead (there is not much there at all). Based on a quick google maps search, there is a private campground at Portage Des Sioux, which is only a few miles away.
Bear in mind, the trail received extensive damage toward the eastern end, with several miles closed from Machens to close to St. Charles. There are some less-traveled roads that you could take in the area, but the trail itself is closed in this area.