OK Camp,
Hang on here...
I can't help you on the hiking, biking and fishing
I don't know how you will get there from London (wife has family there), but however you cross, try to plan a stop at Saulte Saint Marie. There are two good campgrounds in town a bike it the way to get around.
As soon as you can, get to the locks visitor center and see when the next ship is due through. Plan to watch them flush at least one. Also in town are the museum ship Valley Camp and the River of History Museum (close Sundays) the ticket may include the tower. Don't pay extra for it.
From there go up through Paradise to the Whitefish Point Museum. (I liked what I saw, but can't go there again. I lost friends on the Fitz and it still hurts.) The boys should love it. Parking a rig is kind of tough some times, I have been told.
You have Tahquamenon in the plan, that is good. Do both. Munising Falls is fun, and a pretty good walk to get to see it. We have always managed to not be able to do the boat tour of the Pictured Rocks.
On the road west of Marquette is the Iron Museum. It was small, but interesting.
About then we have already blown by the route to the Garden Peninsula (where Fayette SP is) and I am not sure how much father afield you will want to go.
Matt
Matt & Mary Colie
A sailor, his bride and their black dogs (one dear dog is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.