Your problem may be far more extensive that you think. In the third picture it looks to me that the bottom seam where the two panels overlap has rotted away almost to the Vee that becomes the location for the body mount. Not sure at this point what the best method would be to deal with this but dead certain that if you want to do a total replacement, at the bare minimum you need a section of frame that starts at the body mount just forward of the rear wheel house and which is complete and intact all the way to the bumper flange.
The big problem here is that the upper point of the section of damaged seam to which you are pointing lies squarely against the pocket for the coil spring. A major part of cutting away the old frame rail is going to be freeing the inner wall of the frame away from that pocket. That will not be easy because that upper spring pocket was probably seam welded along the upper edge of the rail for maximum strength. Not only that but if memory serves, the pocket is also attached to the rear crossmember at some point and you do not want to weaken that piece of structure at all.
It is too bad you are in Maine and NewmexGuy is in New Mexico. Right now I am personally seeing this as a cost vs benefit question involving the price to do the repair/replacement, given all the potential complications involved, versus finding a frame from the sunbelt as close as possible to you, paying the shipping costs to get it home and doing a complete frame swap.
I get bringing it in from NM is cost prohibitve but there at least a few members on the board who live south of the Mason-Dixon and know of yards and vendors who could have frames for sale; much closer.
I also appreciate that the exchanging of one frame for another is a labor intensive piece of dirty mind boggling work but when it appears that the existing frame is as structurally compromised as the pictures you show of yours seem to indicate that it is, then, at what point does repair become so expensive that replace is actually cheaper?
Nick
