I'll ignore your other points, because sibling comments are addressing them better. So here's something more unique:

> Also the permitting of stuff across state lines is so time-consuming it's effectively illegal.

This is true in general, but in this specific case, there are a lot of obvious ways to get around the problem, because Nevada is a moth-eaten shirt of federal land reservations — Nevada-the-political-entity only owns/regulates ~15% of the land of Nevada-the-geographic-territory.

With the current state of the US federal government, lobbying to privately use one of those federal reservations would be a walk in the park; and once you're going "California -> federal land" instead of "Calfornia -> Nevada", regulation gets a lot simpler.

Fun fact: there's a National Forest in Nye County (bordering California) that runs right up to the edge of the DoE-reserved area where they did the nuke tests. The feds are fine with running HVDC lines through National Forests (they're not Parks, after all), and "repurposing nuked ground for solar" is actually an easy-to-sell narrative at all levels. You could build solar there and backhaul it to California without ever touching land regulated by Nevada-the-political-entity.