Proposals had been made to change Russia's nuclear doctrine to allow for attacking any non-nuclear state that had the participation or support of a nuclear state, Putin said.
Most "middle of nowhere" places in the US are where the ICBM silos are located, so you should still be on track to be completely vaporized by enemy nukes.
also even just taking the dumb premise seriously in order survive you usually have to hunt. maybe he can have some pets or the beans grow really big because radiation lol.
Most likely is that everyone dies including the animals. Earth is uninhabitable until the sun goes supernova, and all that remains is a pathetic gas cloud of a race that couldn't stop itself from being greedy barbarians.