could you let me see a closer picture of the cancer showing. And would you crank the resolution to the best setting.
The answer is yes on replacing old skin but just cut an inch into the good metal. The best way to remove the skin rivets without messing up the skin, is to take a center punch and dimple the exact center of the rivet and drill out rivet. It looks like the rust has crawled under the the ribbed scuff guard( the black trim I would remove that black panel paint seperately before reinstalling. Since its steel, and I assume you can weld? I hope, if not one of your friends should be able to. make the splice under the trim and just lap the new panel over the rivet line, instead of under it. very few people would ever notice that it should be under than over it. The other reason to do that when you paint it all you need to do is run a tap line just next to the new piece of metal, prime and paint since you will be reinstalling the black trim piece. you will not need to blend the paint above the splice. Obviously you want to remove the wheel well molding and paint it as well. or is it rubber.
If it is rubber use a product called bumper black will make it look new.
Essentially you will be replacing a triangle, the top where the splice is made will be covered and left point of the triangle will be covered by wheel well molding and the top molding and the vertical line to the right will be rivetted with the new piece lapped on top so you will have a clean edge. if you must grind the rust off of the area that overlap the rusty piece that needs to be replaced mark with a straight edge a line and grindup to that line mask it and hand paint before over lapping the new piece and rivitting.
since the location is on the side and not on a roof panel using steel pull rivets you can use a butane torch heat flux it and fill the center whole of the rivet with rosin core (not acid) it will wick in and fill the whole just like swetting a pipe joint. sand a little bit and go.
Yes because the skin is steel use steel rivets, If the wholes are wallered out drill to the next size and make sure it is a tight fit.
. If i did not explain it clear enough I can email you my phone number and we can hash it out some more.
really hopes this helps if this as clear as mudd we will try again dale