Some observations:
1) If this is a modern campground nowadays (on top of some yesteryear spot), then go figure: There's going to be modern junkage. Eg.: foil, tabs, zinc, can slaw, molten can nuggets (from persons throwing their aluminum on campfires), etc...
2) Go figure that the most amount of people (and attendant ranger personnel, etc...) will be at the campgrounds. So if there were any worries about doing your hobby there (ie.: the exact entity who administers, and their exact verbiage, etc...), then the last place you want to be swinging is in places where lookie-lou busy-body rangers might be.
3) The optimum place will be if you find removed zones, where no modern camping occurs (and away from busy-bodies), yet that perhaps were the camp zones and/or resorts your link alluded to.
4) the existence of "old mill equipment" might look dazzling. But those might just be "work" or "commercial/industrial" zones. And are not necessarily the locations you want to be detecting. Because the type places you want to be md'ing are where they PLAYED, SLEPT, RECREATED, etc.... Not where they were thrashing about with heavy equipment working (read "iron junk"). Same logic for those that try to hunt gold rush sites: They are immediately drawn to the ruins of sluices, concrete foundations of stamp mills, etc... Right ? (simply because that's the first things your eyes are drawn to). But the reality is you want to find the worker tent city zones where they set up their camps. Of which perhaps NOTHING REMAINS to show such locations.
5) Bear in mind that modern signage always says something to the effect of "park / camp in designated spots only" and " fires in pits only" etc... This is all an invention of the last 60 yrs. or so. In the old days, people would go into camps and just pitch tents wherever, build a rock pit to BBQ at wherever, etc... Needless to say this causes vegetation trampling, etc... So starting in the 1950s and '60s, ecological awareness kicked in, and camping, BBQs, parking, driving, etc.... were restricted to set-up zones. In an effort to reclaim trampled areas.
So for example, one spot I hunted on NFS land years ago, had picnicking and camping that dated back to the 1920s and 30s. And my first instinct was to hit the obvious campgrounds we were staying in. But as I ventured out further into mundane grassy meadows, I was able to find yesteryear camp zones (tell-tale by trees where people pitched rope between 2 trees and pitched tents, etc...). But you would not recognize them today, as they've been reclaimed by the forest, grasses, meadows, etc....
Thus if you can deduce where some of your links resorts and camping was THAT IS AWAY from modern influences or industrial junk, then THOSE are the places you want to find
