Gary,
Changing your serpentine belt is a very simple task. There are only two things to remember. One is if you do not have a belt diagram, draw a sketch of the belt routing before removing the belt to be sure that you route the new belt properly. The other thing is to be sure that you get the right belt, and since your old belts are still in use, you can just take them to the parts store to match them with a new belt. You can not go to a parts store and tell them that you need a belt for a C 15 Cat engine because the accessories were specified by Monaco and not Cat, so it is easier to match the belts unless your owner's manual list the belt numbers, but the owner's manuals on these coaches are often wrong, so match the belts.
Gerald