I suspect you might have damaged house battery voltage sensing circuit in the battery control center. This circuit controls the battery disconnect solenoids and the cross connect to get power from the engine. Need to know the manufacture, model and revision number for a better idea what and where to check. One thing to try is next time you lose house 12VDC hit the AUX Start switch (with the engine off) and see if the lights come back on.
Really surprised the fridge controller didn't cook and it still operated on LP. Would have been interesting if you had tried to extend a slide (assuming they are electric and not hydraulic).