CE has explained the deal with the extension courses - IIRC, they still had to be attended in person but in a different place or something? I could be wrong...
Ann registered at UW in August/61 and used the address of the Capitol Hill apartment as her address which means she took the extension courses while living in WA state at the Capitol Hill apartment and was still in that same apartment in fall of 1962 when Barbara Cannon Rusk visited her.
See post #6992 for the article about living in WA state and attending UW. There are two other articles which were written about the Capitol Hill apartment but this one contains details which the other articles didn’t. Please excuse the source but you have to go where clues lead you!
No attendance is typically required for Extention Coursses. Enrollment and assignments are completed by mail. At most, a proctored test in the attendees own location is required. Most degrees limit the amount of credit that can be accrued through Extension Courses. The course can be taken from any location, even Kenya!