Thank you! That describes what I see. So I don't have an immediate problem, but do have a system that is grossly out of conformance with modern specs.
Not only do I have that obsolete layout, worse is everything at both panels is Federal Electric - a comiii9pany now out of business because their stuff caused fires. I'm careful to never load any circuit to near breaker capacity. Thankfully this isn't our primary residence, we spend most of our time now at the ranch but have a house in town.
Photo: Worst example of how obsolete (and amateurish) the farmhouse wiring is, under the house in an area made inaccessible by a later remodel. I hope the wiring in the walls isn't like this.