Another good one is Mt. Diablo to Mt. Lassen, which is around 180 miles. That's the longest one I have seen in California. Tom Stienstra claimed it's 180 miles, which is a long way. [1] Other sources claim somewhat shorter distances.
Mt. Lassen, ha. If the atmospheric conditions are good enough you can see Mt. Shasta from Mt.Diablo. I know, I have seen it. That has to be around 250 miles (I don't have the exact figure). That would be 402 kilometers and worth a mention on this list.