Even for planning for personal travel, it's worth noting the massive difference in the amount of tourism between America's top 5 or 10 National Parks, and the countless other National Parks, Forests, Wilderness Areas, etc.
Yes, Yellowstone, Yosemite, the Grand Canyon, and a few other places are absolutely crawling with tourists. They're victims of their own success as destinations for people to check off a bucket list.
But once you get outside that top tier, America has countless places that are just as beautiful, still legitimately wild if that's your thing, and definitely not as crowded.
In my neck of the woods, the Blue Ridge Parkway and Great Smokey Mountains National Park (which are among the most-visited in the country, by the way) don't have the same sense of overwhelming crowding that, say, Yosemite does, except for maybe during peak leaf season, or at specific times/locations (e.g., Cades Cove in Spring). Most of the year, sure, they're not pristine wilderness, but it's not like they're wall-to-wall people and trash, either.
And, if wilderness IS your thing, you can go right next door to Pisgah National Forest or Nantahala National Forest, backpack for miles at a time without seeing another soul, and see views that are, IMO, equally as impressive as what you get in the official National Parks.
I guess what I'm saying is, if you're looking for a more remote experience, venture away from the big-name National Parks, and hit some of the lesser known areas, and you'll find that America still has a ton to offer.