Morning all, and thanks for all your comments and information. Very helpful! So I had both chassis' batteries charged with trickle charger (external) to 100%, plugged in the 50 amp plug, by way of converter overnight. This morning, she is dead as a doornail again. Not even enough chassis power to "click" even the generator, let alone turn over the engine.
These also look like original batteries, which would make them at least 4 years old, and I have no record of how they were maintained. Silverleaf also has no power, so there is no way to "see" what's happening with the power distribution.
I am now looking for two replacement batteries, at least then I will have a known starting point.
Wet behind the ears in St Paul!!