US West Coast trip

[fiatpower]

I am planning a 4 week long west coast road trip with my girlfriend for August. I've already done one long distance trip around California and then along route 66 to Chicago so want to do something different.

My very rough plan (no timings as yet) is as follows:

Fly to Vancouver
Seattle and spend some time around there including the Boeing factory in Everett.
St Helens
Yellowstone National Park
Salt Lake City
Las Vegas
Yosemite National Park
San Francisco
Monterey
Santa Barabara
LA
San Diego
Fly from LA or San Diego

I am planning to drive between the various locations at the moment but I might decide to fly some sections if there isn't anything to see. The distance doesn't concern me as it's a very similar mileage to my first trip and found it manageable in a shorter time frame. Does anyone have any ideas as to what to see on the following legs:

St Helens to Yosemite
Yosemite to Salt Lake
Salt Lake to Vegas