It's not difficult. The upper latch assembly is held in place by 4 phillips-head screws on the inside. You might have to remove two screws on the edge of the door -- I can't remember.
The key blacks are not stocked by most locksmiths and have to be ordered from either Trimark or Airstream. Third-party blanks (ilco, Curtis, etc.) will not work reliably.
To learn to see below the surface, you must adjust your altitude