You may find a lot of that era elect boxes are metal with metal retaining clips.

Like @Troy Sheets mentioned it is likely a dead short somewhere in the circuit, could be as simple as the hot leg on the recepticle shorting to the grounded metal box (assuming its a metal box), Or it could be a pinched staple or melted wire, hundreds of other possibilitiesIf its a melted wire you have a bigger problem, there should be no possible way a standard gauge wire could carry enough current to melt the wire.

then they climbed the rock up to the cedar siding along the rain gutter downspouts , they would get into attic I would fix the spots with hardware cloth Or you can use metal lath in my case they just found another way in over and over (this stopped after I found the baby's , heard them squeeking and caught them and put in a bucket with hole in lid and wired it on to a treelimb) P.S If you grab squirrel baby's that are very big grab fast they are quick .

Dents in metal of appliances and doors.

I highly recommend metal roofing.

If its in an old narrow metal outlet box the GFI screws may be shorting out against the metal walls.

Most cheaper/affordable cookware is sufficiently thin that it quickly warps an will no longer sit level on the stove;second, if a tenant damages the cook surface on a coil-top range, you simply replace the coil.  

In the crawl space, maybe right before the cables go through the outside wall, coil up a couple of feet of extra cable - this lets you do tricks later like cutting off the last inch of cable and installing a new connector.

We sold it after my Mom had lived there over 50 years.It was built with a crawl space and metal "termite shields on each post and the CB foundation.  

@Matthew John Your tub should have an overflow drain, behind the metal cover plate.