The challenge might sound easy, but here are the parameter restrictions:
-All PoDs must be after the Korean War armistice & post-Truman.
-The US cannot have deployed ground force units in Vietnam or launch bombing of North Vietnam [you have flexibility on the level of aid and advisors present in South Vietnam]
-The endgame must include a US President visiting the PRC by 1972, and US recognition of the PRC as the "China" by 1979