I want to share a calendar with 3 or 4 other people. I am looking for the simplest approach; one user is highly non-technical. I tried using Google Calendar but she would keep adding events to her personal calendar thinking it was the shared one. Under the "My Calendars" heading, I selected to only display the shared calendar but it appears Google Calendar by default re-shows the personal calendar after a new event is created. Can this be changed? Is there a simpler alternative to Google Calendar?
Indeed, Google displays the personal calendar as the default one when creating an event. The simplest option would be to ask her to share her calendar, without sharing details (just busy times).
See also this question about merging duplicate events from the personal calendar and the shared one - it might help to install that extension in her Chrome.