My question is did the batteries last for the trip? That gizmo on the wall is worthless for testing battery capacity. It is only a simple volt meter and not very accurate. The difference between 4 lights and one is about 3/4 volt. You can make a full battery show empty by simply turning a lot of load on at same time.
After the coach has been on shore power for at least 24 hours you can check charger float voltage with a volt meter. It should read 13.3 volts. If so, the charger is working fine. If higher, it is still charging the pack and if lower, it has a problem or there is a bad battery.
I have been in the desert for over 3 decades but I grew up camping in those south MO. parks. Alley Springs has many fine memories for me. I envy your trip to Meramec!!