I am very sorry to hear about your troubles. Owning a classic AS motor home you will become accustomed to surprises. What's with Good Sam and 5 hours! They send me a letter a day stating their tow truck will be there instantly! Not only that but a special tow truck just for motor homes! Sounds like the Dallas area never read the advertisement.
There are several causes for your problem. I would first check all fuses, second the fusible links. Third, is your charging system, how much juice do you have in your starting battery? Do you have power on the coach side? There is a small resistor wire that runs from your ignition back to the relay switch between the starting and coach batteries. If this wire breaks you will loose all power to the ignition switch. The wire is tan on my coach. I am attaching a picture of the location of the fusible links for you, thanks to Peter H. This is on his coach not my diesel.
Good luck to you.
1994 30' Excella 1000, Chummy III- Ford Excursion- 7.3 Turbo-diesel