Patch,
I have the same genset as your coach and did the belt last summer. After 'reflection' on the safety cage surrounding the belt/waterpump/alternator assy I decided to get the cage off as expeditiously as possibly (to include cutting, hacking and otherwise destroying) as the working conditions were tight. After I got the cage off I replaced the belt and scrapped the safety cage. It serves no purpose on my coach as the genset is located amidships between the front seats belowdecks. Little chance of anyone poking their fingers around it while running. I believe the safety cage was for applications on this genset where the entire unit would be exposed such as a marine application where someone in the engine room might accidentally lose an appendage if caught in the belt.
Mine works great without it. Coach lost a couple pounds.