It says at the end, she'll rent out the rooms. San Clemente is in prime beach front Orange County. 1) She will be able to rent a single room for at least $750-$1000. 2) The property is in a highly desirable, wealthy area and will likely continue to grow in value over time. 3) Her earnings will grow over time once she graduates.
That's a lot assumptions... 1. that she'll be able to rent the rooms 2. she'll be able to get a job where she lives.
I'd be scared s* if my $610K mortgage depended on getting a job and renting out multiple rooms every month.