1) Photo 1 - old muffler was badly rust-damaged. The support hanger was also rusted through. (The replacement hanger was not available at the auto store so I ended up fashioning a temporary one.)
2) Photo 2 - The old muffler was rusted right to the frame so I used a Sawzall to cut through the pipe on either side of the old muffler. (NOTE WELL: The Sawzall was throwing off some sparks so I put a piece of thin steel between the cutting area and the gas tank).
3) Photos 3-5 - I also removed the tailpipe and sanded a lot of rust from it. I then sprayed it to, hopefully, slow the remaining rust.
4) Photo 6 - Old and new muffler comparison.
6) Photo 7 - Propping the new muffler (or hanging from a wire) was helpful during installation.
7) Photo 8 - Here's the temporary hanger, which I fashioned from steel used to hang duct-work. Also, for some reason, there was a lot of play between the pipe and the new muffler, which fits over the pipe. So, I shimmed the gap with nails. It took a huge ratchet to sufficiently tighten down the clamps. (Here, it might be worth checking with the auto store to see if they make a spacer to help get a closer fit.)