The most easily identified formation in the Park. There are 4-5 good routes to the top, and a massive eye-bolt at the top for your descent.
Either hike up the Balanced Rock trail and head East on the East Bluff trail, or hike up the Potholes trail and turn West when you get to the top. The Doorway (as well as Major and Minor Masses) are on a side trail that loops off the main East Bluff trail.