Kennedy would have a much better shot at the nomination than he did in 1968 with his brother's assassination on everyone's minds and early '60s optimism still in full swing. I suspect he goes for it, losing a bit of ground especially in the South but still winning big. Humphrey's map would look about the same, losing a bit of Johnson and to a lesser extent RFK's rally round the flag effect.
Attorney General Robert Kennedy (D-MA) / Governor Terry Sanford (D-NC)
Senator Barry Goldwater (R-AZ) / Congressman William Miller (R-NY) ✔