And in the process found some surprises. I've been trying to hunt down an inverter short that has prevented me from watching TV while boondocking. I figured I would start at the batteries. I had dreaded this because when I had tried before, the slide out that the batteries sit on was jammed. This time I soaked the rails with some penetrating oil and was able to finally slide it out. My first surprise was that a rodent of some sort had decided to make the battery compartment its new home. I found his carcass after cleaning out all the vegetation that he had packed in there, not to mention all the poop.
My second discovery was that the house batteries were not deep cycle as I was led to believe. They are, in fact, heavy duty truck batteries. Think busses or 18 wheelers. Both read 13.5V with a tester, and both were dated 2018. I have used this rig solely on shore power but I am planning on an extended boondocking trip so I need to decide if these will be up to the task. If they were older, or reading lower, I would replace them now, and I could probably use some advice as to whether I can use these in conjunction with the generator for a few weeks.
I still didn't find the inverter short, but at least now I have a better understanding of my batteries and how they are wired.