I would interpret Rule 17 to mean that all other aircraft are beyond the holding points, as the purpose of holding points is to give a safe separation from the runway. I never call "runway vacated" until well clear or beyond the hold.
When vacating onto an intersecting runway, or "across the grass" it ought to be an equivalent distance. I guess it would be down to the court to decide.
At unlicensed fields it must really come down to good airmanship.