This. If you've not seen them, I'd recommend the following, in my order of preference (bolded I've been to, all the rest I want to):
Glacier
Grand Canyon
Zion
Grand Tetons
Yellowstone
Olympic
Black Canyon of the Gunnison
King's Canyon
Yosemite
Mt. Rainier
Crater Lake
Bryce Canyon
Work out a path covers a few of these, and you won't be sorry. If you're going to Seattle, for example, it'd be easy to ht the The Grand Tetons, Yellowstone, Rainier, Olympic, or Glacier as you go. (I wouldn't recommend doing all of these, but they're all in the area.)
For SF, the Black Canyon, Yosemite, Grand Canyon, Zion and King's Canyon are all doable.
It all depends on how much time you have. Spend at least a few days in each place you go (I prefer a week, but it's hard to have that much time on a road trip).