Quoting: Andy
Also, does the green line cut mean you'll be welding in a new rail section with shock mounts on it? Can't quite tell from the photos. If so, this would take quite some work to get all the alignment sorted.
The leaf spring mounts in the round tube at the back end of the rail (where it's currently rotten)
The bracket nearest the green line is the rear anti-roll bar mount. The shock mounts outboard and up from this, you can make out the square edges of the space for it, just under the green line.
My current line of thinking, based on these and other comments on the 2nd gen forum, is to strip off the floor from the donor. Start cutting the old rail near the end and move back until I am happy the metal is solid, i.e. cut as close to the bumper as possible. I think I will be able to butt weld the outer side of the rail and rear end to locate it, the cut out the floor above/around it to get access to finish the weld on the inner edge, and also allow me to weld it from the topside of the frame for added strength.