This particular skylight installation in Lake Oswego had both fortuitous and difficult elements.
The fortuitous elements where the vaulted ceiling and the horizontal structural beams that made accessing the opening somewhat ideal from the interior.
The difficult elements pertained to the relatively steep slope of the roof and the fact that there were three layers of roofing.
As you can see in this photo, as well as the second of these photos, the first layer of roofing was cedar shake. If you click on the photo, you may be able to see it in a little more detail.
This can make the flashing portion of the installation a bit challenging. But challenges are what sharpen our skills and makes a completed job like this quite satisfying.