Well it also depends on the time of year that your vacation will start or stop.
You do not want to end up in Yellowstone in May, unless you really like camping in deep snow! Same with the North Rim of Grand Canyon, deep snow, and sometimes the main road is not clear of snow until mid-May.
Texas, you don't want to be in Big Bend in July, or Death Valley. Why go there when it is 105F or warmer? Those are great places to visit in November or March.
Zion NP or Bryce Canyon are great places to visit most of the year.
Good luck,
Fred.