Having pulled a trailer with my Gm PD4106 I'm alway suprised at the comments regarding pulling a trailer with a GM coach considering most, if not all, the people responding had no actual experience doing that.
While I may not have direct experience jumping off the roof of my house, I know it is not a good idea due to other facts, experiences & training. A college class in vehicle dynamics will have you amazed at how they stay together as long as they do!
5 out of 6 people who play russian roulette live, but that doesn't mean it is safe to play.
There have been a few that have posted negative results from pulling heavy trailers behind buses.
The fact that most busses were not designed to pull trailers reinforces my opinion that trailer pulling with a bus is not to be taken lightly.
Mr. Vickers was kind enough to post the bus numbers that were used to pull the trailers. Let's find some of those & see for ourselves what was added (if anything) to allow trailer towing. If none survive, that should also tell you something.
Personally, I hope all those 4101's are out there & easy to find as I'd like to know what I need to do.†
If you want to pull a heavy trailer with a bus, knock yourself out. I'm just trying to give you something to consider so you can minimize the unexpected & have safe & happy travels.