...this happens in winter time when folks dont clean the salt from their shoes off well enough. doesn't see to really be a drainage problem... anyway, i'm thinking i could rivit a small metal plate under the hole and then rivit another smaller plate (only a few sq "). to the lower plate and then fill it in with something like por 15 and apply a little spray paint (in my case orange) to the surgery...
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would appreciate any alternate methods.
thx,
flaps

Your little rust is likely something much more extensive. I was working on my sills and started with a spot about the size of the ink tube in a ball point. Hit it with some sandpaper and suddenly it was the size of a silver dollar! These things rust from the inside out. Putting a plate over it will only cover the bigger issue.

If the rust is not too extensive, I would pull up the carpet and pop out the plastic plugs, then clean inside the sills the best you can. Sand down all the rusty areas on the outside. (And be prepared to find more than you expected!) Treat the inside of the sill area with some Metal Ready, then try to coat the entire inside with POR. Treat the outside with POR as well, then either weld in new metal or use automotive panel adhesive to glue on a patch. Prime and paint. This is a short-term solution, but might last a few years.

I doubt salty shoes caused your problem. If you look at the wheel well for the front wheels, you will see a metal panel at the rear of the wheel well. It was originally sealed against the body with a rubber gasket. I think a lot of rust in that area is because the rubber seal dries up and goes bad. As the car goes down the road, water and dirt get slung against the panel and find their way into the dark nether regions along the back part of the fender and the door sills. You might want to pull that panel and give the inside area a good cleaning. Treat with POR and find a way to re-seal the panel.

My PO had actually bent the top corner of the panel away from the fender, presumably to allow some ventilation????