Fort Wilkins camping area is nice. There is plenty of grass and trees. The old fort is right next to the campground and an interesting historic display. The area's history is about mining and forestry. Copper Harbor itself is small, but there are places to have a bite to eat.
You might want to drive along the Lake Superior shoreline on M-26 to Eagle Harbor. There is a very good little bakery there run by monks that is worth a stop.
Estivant Pines has some short trails for a hike, but it has some virgin forest areas that are very nice.
Please note that once you get to the Houghton/Hancock area the trip from there to Copper Harbor is a bit slow going due to hilly and winding M-41 with small towns.
If you have time you might want to get down toward Ontonagon where you'll find Porcupine Mountains State Park. There is a state park with electric/showers on the north end of the huge park and a rustic CG at the south end. This park is very large and has many hiking trails, waterfalls, and scenery. One of my favorite places to hike is at the south end of the park near the rustic CG. You can hike both sides of the Presque Isle River from a parking lot closer to the CG or from South Boundary Road (the road that goes around the park away from Lake Superior). There are several falls along that stretch of the river with plenty of overlooks and you can even walk out onto the rocks in places.
There is also a small roadside park just north of M-28 & US-41 intersection called Canyon Falls. It's on the west side of US-41 and you'll miss it if you're not looking. There is a short hike back to the canyon and worth the time.
In regard to Fort Wilkins being crowded, I don't think you'll have too much of a problem. My last trip up there was about 5-6 years ago in mid to late July and the CG was not busy. Porcupine Mts. may be busier.
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