I'm based in Utah. Its just my wife and me. we have covered some of Colorado, Oregon coast and northern California, spent time in most of Utahs great canyon-land areas , I'm sure we will still find mo...
You would have plenty of time to do Yellowstone and Glacier; or Yellowstone and Tetons; or Yellowstone and the Black Hills. The theme there is to do Yellowstone. If heading west, Yosemite and Sequoia would be on the list if you have done them before.