"King's Row" is an expression that means everything is going really well as much as it is a way of saying you, the speaker, appreciate the other person whom you are addressing.
It is not a reference to the 1942 movie directed by Sam Wood that featured Ronald Regan. Ann Sheridan, and Robert Cummings.
It has originated among snowboarders, skiers, and locals along the California/Nevada border in the Tahoe Basin.
George Grey: "Hey, how's it going?"
Oscar Pistorius: "King's Row, King's Row...(mate, man, buddy, friend, amigo, brother, sister, etc)!"