I tend to use a bare minimum of work scaffolding, I added a triangle of pieces under the structure to rest a plank on, then added more cross timbers and the end piece.
The cross beam has a 2x4 screwed along it back edge which forms an overhang into which the rail for the sliding door is screwed. There is a hole that runs down through the timber and the rail so that the runner heads for the door can be attached and adjusted. I made several copies of the top curve at home to make various parts of the roof. I wasn't sure why I left a nubbin of the end piece sticking up from the roof line, but it ended up forming a tenon that slotted into a nose piece.
The sliding door would not have worked well had I not trued up the scaffolding frame.