>>1288254Many of the big-name parks (Yellowstone, Yosemite, Zion, Arches, etc.) get insanely crowded during summer. We're talking hours-long waits to see throngs of tourists blocking the views. They'really really special places, bur for the love of God, go in the off-season. Yellowstone in winter is amazing.
I imagine you'll be hitting the Utah parks. Since I'm from here, they're what I know best. Canyonlands is easily the most /out/ of them, but the most accessible part of it is the Island in the Sky. Don’t bother with Island in the Sky. You woukd want to get a backcountry permit and spend a few days in the Needles or the Maze - if you don't have time for that, skip it.
It's worth seeing some of the spectacular parts of Arches / Zion, but realize they're going to be packed and plan accordingly, i.e. get a feel for what they have to offer and then hit the road.
Also in Moab - Fisher Towers is definitely something you should at least drive by. The road continues to become the LaSal mountains scenic byway if you're into that. Dead Horse Point is a very cool overlook that you can drove right up to.
Everybody skips Capitol Reef. It's nice. Go there for some slot canyons. The San Rafael Swell also has nice slot canyons and the like, although it wasn't developed for hiking the way the national parks were. A lot of this depends how much time you have - Arches and Zion are rightly loved by tourists because they can spend a few hours, get some stunning views, and be home for dinner. Canyonlands and non-park areas, not so much. Capitol Reef is a good compromise imo. If you head to the Grand Canyon from Utah, you'll drive by the Glen Canyon Dam and Lake Powell, which are surreal.
Cedar Breaks is a slightly smaller Bryce Canyon with about 1/20 as many tourists.
There is very little in Bears Ears / Grand Staircase that you can't find better versions of elsewhere in the state. Skip them.
Also this
>>1288269