At that time you had two options get married or take a vacation to a home like you described.....She got married....No need to go to home....In fact most homes would only accept UNWEB mothers, not newly married....and now we know they were indeed married...cause they got divorced.
Unless it was a marriage in name only to protect the status of the baby. She talked to her friends in Seattle about her marriage and her exciting husband even though she had already left him and was in WA to go to school. I think it was just to provide a cover story. And with the home, she could have just claimed she was unmarried—why would anyone check into it?