When doing a Youtube search we found someone has recently posted the GMC Motorhome Training Tapes.
Now, you may have to be a GMC Motorhome fanatic to want to sit through these videos but they are very informative. Part 2 does not have the audio but the other videos are narrated. The first video (tape) goes through the entire motorhome and how things work.
Here is a link to the YouTube Channel which has various videos including the Charging System. There is also a video on how to repair the door if yours is wonky. Needless to say we are knee deep in watching these videos, guess Comedians In Cars Getting Coffee will have to wait!