Ron,
A local guide here. We don't camp when we go to The Henry Ford, we are a little long on walking distance.
There are three campgrounds that I might consider:
Wayne County Fairground is closest. Pretty much treeless. Not bad, but nothing to write home about. It is typical fairground but some is FHU (maybe all by now). 19 miles
Detroit Greenfield was a KOA once, and it is a prettier place. Largely shaded. 24 miles
Camp Dearborn is very nice, but the trees in the newer sections are not mature. Camp Dearborn is allied with the Henry Ford and did offer discounted tickets. 38 miles
Parking a coach at the museum/village is no small feat. I also suggest that you get on their website and decide what you want to do. Even if you plan a day in the museum and another in the village, you will be running on overload much of the time. I still am and I used to volunteer there.
As you will be coming in from the West, I hope you will use I-94 as I-80 in Ohio is a toll road.
Have GasBuddy running, you will probably want to fuel up in Indiana (Portage area) because fuel is more expensive in Michigan.
Are you auto or aircraft museum people? Because if you are, from I-94 you will be in striking of both the Kalamazoo Air Zoo (used to be a collection of Grumman Cats) is a great stop. A good bit farther off the highway is the Gilmore. This is a place that defies description as the collection is amazing. It is in many buildings and requires a lot of walking. The do have a dry camp area, but I do not know the cost as it in our "we might as well go home" range.
If you have questions, I'm here a lot and I do try to read private messages.
Matt