There's a fellow on Reddit who has been doing some interesting work modeling a notional RISOP — basically, what the Russians would do to us in various counterforce & countervalue scenarios. He cannot comment on SIOP planning as he used to work on it (civil engineer by training), but he can conjecture a RISOP based on open sources.

This person makes a point of targeting American dry cask nuclear waste storage sites. It takes out the power plant they're next to and ruptures the casks, resulting in Prolonged Suck downwind of the site. He also targets dams in a cascading manner, so even if we did "win the war", certain major cities would have been underwater for a sustained period of time.

FWIW, when asked where he'd go to hide out he said he wouldn't, that the loss of food supplies, medicine, etc. would be catastrophic no matter where you ended up in CONUS. Re: food, even if the grain fields of the midwest were intact, you've got no transportation, no power to process the grain into food products, no antibiotics to take care of that scratch you got from the combine, no fuel for the combine, etc. Many would survive but it wouldn't be fun. He lives in San Francisco, FWIW.