I think it would start out one of two ways - a precision weapon to take out the ICBM pre-launch (and hope Phat Wun gets the message), or it would be shock and awe - massive nearly simultaneous attack with cruise missiles and stealth bombers to take out the air defenses, quickly followed by nearly every available aircraft carrying as much as they can carry.
Don't fool yourself, North Korea is probably the most thoroughly mapped area on earth, with every suspected weapon site cataloged. I suspect a fair number of drones are monitoring NK as I write this (and they have pretty good night capabilities, quite different from the 1940s)