No, unfortunately it is not possible to use Advanced Form neither without Scheduler nor by setting it's property Visible = "false". The reason is that Advanced Form is not an independent control, but part of the RadScheduler.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!