The kiln might be good for a few more years of firings in spite of its age. The bricks may not be as bad as they appear. If you can buy the kiln for a song, and you have the circuit already installed, maybe you should consider it. Make sure the elements all fire. Check the amperage. Look for rust. Make sure the Kiln Sitter works.
In addition to placing the cone on the opposite side of the firing chamber from the peephole, align the cone so the bottom third is silhouetted by the element. Thus, the cone will still be silhouetted by the light of the element after the cone bends.
In some kilns, the center elements do not glow brightly even at cone 6. To see the cone, you may need to silhouette it against a top element instead of a center element.