rear window rust repair

[beautimus]

recently, i noticed some rust bubbles around the top of my back window, after some poking around on them i soon had a rust hole about 1 inch tall most of the way across the inside of the cab.
talk about heartbreaking!!!!!!!!!!!
the exterior of the cab seems fine. apparently the gasket around the cargo light has been leaking. so i guess i am lucky that the exterior is still solid. so i go out to my trusty parts truck and
the back of the cab is okay. so here is the delima, do i cut out a
small patch from the parts truck or do i drill out all the spot welds
around the door openings and the rear window and replace the whole panel? (the inside back of the cab panel attaches at both
door openings , the window area and the long seam above the window.)

what do you guys think? anybody here tried this?