Site seeing ideas Seattle to La and then across to LV

A mate and I are Driving down from Seattle to LA and then across to Vegas from mid Aug to beginning Sep. 20 days of travel time.
We would love any up to date ideas on places worth visiting. We looking to at least spend 2 days in LV, 2 days in LA and 2 days in SAN Fran. We havnt planned much as we like the idea of “spur of the moment”. Any ideas of where to target would be awesome.

Thx

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