Replace muffler

[cdat]

I have the 91 coach at the Cat dealer to get some initial services done. They found a hole in the muffler, I decided as long as they had the coach to go ahead and replace it. Now, they are telling me that because the entire exhaust system is welded together that this is going to be a major project.
1. I've replaced mufflers in the past that were welded, we simply cut the old one off, then had a new one welded in place, is there a reason this is more difficult on the Newell?
2. Is there anything special about replacing a muffler on a 91 Newel that I'm unaware of?
3. Anybody aware of the cost of a muffler for a Newell?

Thanks for any advice.
John