calendars

I have a client who's been using an ancient (by web standards) Perl-based calendar script program (called, dully enough, "CalendarScript", which hasn't been updated in years.

I've recently converted other parts of her site over to Drupal 6.x, and have been strongly recommending moving off of this old calendar script out of both security concerns and usability reasons. However, she's used it for many years and is reluctant to abandon it.

I wanted to poll this group to see what is the best way to manage access control multiple calendars in drupal.

I have a site where I need to be able to create some calendars public and some calendars private.

I need to control which users / roles has permissions to add an event to the calendar and which users /roles can view the calendar's events.

So far the only techniques I can think of are
1. Use Event content type with tags - create a vocabulary for Calendars with each term as a calendar - restrict with a taxonomy access control module