I hiked the length of the park over 5 nights on two different trips. The eastern side of the park is definitely quieter and less populated than the western half, but even the western half is pretty quiet except near Chapel. Despite not seeing many other hikers, it was clear that the trails were well-traveled by inexperienced hikers unfamiliar (or apathetic) about Leave No Trace - there was SO MUCH toilet paper along the trails and perimeters of campsites, even at Mosquito River where there is a pit toilet. 

My site at Lowney Creek (#4) was wooded and had way more mosquitoes than the other sites at that campground. There was an abundance of raspberry bushes around camp, which were a nice addition to my morning oatmeal. 

Mosquito River was the busiest of the campgrounds I stayed at, but the ability to go sit on the sandstone in Lake Superior at the end of a long hike was well worth it. 

Cliffs has no water source at camp, but did have some small (possibly seasonal) streams closer to camp than the Miner's Castle visitor center. Had I known that these existed, I probably would not have carried so much water from Miners and instead filtered from these sources.