We managed to find American-made replacement anode rods, and there's a new one at the top in this photo. Below it is the old rod that Lisa removed from the water heater. You can see how much decay there was. Lisa thinks this might have lasted one more year, but it was not a problem to replace it now. In a past replacement, there was virtually none of the rod remaining but the thin core, and that's waiting too long.
Removing the anode means draining the water from the tank, but that's only six gallons of water. Zoom in and you can see how much hard water deposits end up encrusting appliances like this around here.
Eventually we need to look into replacing the anode in the big water heater in the house, which fortunately won't require draining the heater because the anode comes in from the top, but it's also going to be more complicated than the travel trailer's anode.