The first thing that I did was detach the door from the freezer. Each hinge is attached to the freezer with 4 screws and to the door with two screws. Since I was planning on building a collar onto the door, all I needed to do was remove the screws attached to the door and leave the hinges attached to the freezer.
The door consisted of 3 basic parts:
1. The rubber gasket that runs along the bottom of the door to provide a seal to the rest of the freezer when it's closed.
2. The white plastic lining which forms the inside part of the door.
3. The outside part of the door which contains insulation.
All of these parts were held together by 4 screws and several small plastic push-in clips that are easy to pull out with a claw hammer and could easily be used to put the door back together in its original state.
(I apologize for not having more detailed pictures of this but I didn't start taking pictures until the door was already off and taken apart.)