One-way honeymoon boat trip to Kenya, marriage takes place there, he flies back to Honolulu for spring semester and she stays with his family till after Barry 0 is born.
That is plausible. Although IMHO still kind of unlikely More likely a two way boat trip starting as soon as U of HI finished the Spring '61 semester. She might have planned to stay in Kenya after the birth, but after finding out about the reality of polygamy, changed her mind, but then was stuck until sometime after the birth.