Red, You may be getting a little frustrated now, but from all you have posted I don’t think you have electrical problems to the extent it may seem to you.
First, your batteries needed replacement. Not unusual and certainly not a failure of the coach. The lesson is they were likely failing for some time and you might have been unaware of their inability to hold a charge or that they were showing some other signs of needing replacement.
Until the alternator output is confirmed (and it sounds like it is OK) that seems to be working as it should. You can stick a meter on the output and measure the voltage and within a few seconds verify it is working or not.