We seem to have a very similar view on what makes our national parks great. I’ve been thinking about a little road trip to a few of them, would you mind sharing your favorites?
Canyonlands. This place is enormous, and the diversity of terrain is amazing. After visit Arches the day before and not loving it, I immediately fell in love with this place.
Rocky Mountain. I went just as the first snow was rolling in, and think this is a great place off season. Gets busy with better weather though from what I understand. YMMV.
Redwood. Not as wild, but great hikes in solitude and not crowded.
Olympic. The sheer scale of this place is incredible, and again the diversity is amazing.
I really wanted to go to Lassen Volcanic and North Cascades, which I believe will be similar, but weather and timing were not on my side.
I've been to just about every national park in the lower 48. Here's some of the less-well-known ones:
Great Basin has a good hike to the peak, a cave system with guided tours, a nice (summertime) campground, and hiking trails to a really impressive arch.
Mt Lassen has a bunch of hikes, geothermal activity, lakes for swimming, a bunch of campgrounds, and some low-frills cabins.
Arches is always way busier than Canyonlands, but there's also a ton of non-NP features around Moab that are even less trafficked. Natural Bridges National Monument is also great. The Notom-Bullfrom road in Capitol Reef is a beautiful drive, and the campground out there is no-amenity, low-traffic.
Sand Dunes, in Colorado, is super cool, with hundred-foot-high sand dunes, but probably only 1-2 days worth of stuff to do in the park itself.
But if you want beautiful scenery without a lot of people, skip the national parks and look for the national forests. (Or sites in the National Park System that aren't National Parks, like National Monuments etc).
This is a really good point re: National Monuments and Forests. I also found just driving the Pacific Coast highway north of LA county as far north as you can go a different but similarly spectacular experience to many of the parks, with good trailheads and stopping points at various state parks along the way. Obviously a much larger driving commitment, though.