Sorry you have not had any response to your questions. I am in Ontario about 60 mi. north of Detroit, but not knowing what kind of campgrounds you prefer, or what sights you might be interested in, it is hard to make recommendations.
One thing I can note is that if you enter Canada at Detroit, you will be on the 401 Hwy. which leads you east into the traffic hotspot that is the Greater Toronto Area. If you search this forum on the 401 and Toronto, you will find advice on the best time of day to avoid the parking lot that this area can become. By the way, the 401 from Windsor/Detroit is not terribly interesting, but does have fuel/food service stops en route.
Google Maps will want you to take the 407 Hwy. which is a toll road. It does avoid some of the worst of the Toronto traffic, but can be pricey for a truck/trailer combo. The 407 has reciprocal agreements with many states and will bill you (there are no toll booths).
From the 401/407, you will probably take 400 Hwy. north. This is also a "hotspot" for 50-60 mi. on certain days and times, particularly on weekends, as many locals head north.
There are several provincial parks with camping off the 400/69 route. Reservations are available, but there are unreservable sites available if you get there early enough.
For what it's worth, we usually go through Michigan to travel to Northern Ontario, but as you are headed further east, six of one, etc.
Hopefully, others can give you more (and better) advice.