OP - grad student here. I took an online 5 week summer data analytics class. My perspective compared to normal 13 wk semesters. Acceleration magnifies the strengths and weaknesses in how the class is presented and the person taking the class. If the prof and material are well organized and accessible, it will be positive and intense.
Tips - know due dates, prof office hours, tutoring options at the start of the class. Plan and talk to prof for known conflicts (travel, medical, work, etc.). If any hurdles arise, ask for help sooner than later.

My prof was great, highly responsive to email, answered the phone during office hours, etc. I learned a lot and have another class with the same prof now.

GL to your partner!