I don’t think A body cut would be much use for those small bits , I do think it’s much worse than the outlined area, perhaps a bit of poking about before sourcing parts
every thing around the areas seams good ae its all being done outside i do not want to cut until i have something to fill the holes with
Hit it with a hammer and tape plastic sheet over the hole that results, and buy the bus a decent cover to stop rain falling directly on the covered hole... You will not like it when you try to butt weld your small patch into a hole that just keeps growing as the welder burns through the thinned metal.. If rust has come through from the back of the metal.. expect it to have spread a fair bit further on the inside. Be prepared to make up something to keep the weather out while working on it when you run out of time at the end of the day. when I did my front panel, I made up fishplates to go across the gaps and basically screwed the old bit of metal back in the hole with self tappers and then taped along the cut, and removed it for the next session of rot repair the next day behind the surface panel...working outdoors in Feb to March..
Looks not very solid from the pictures , unfortunately gotta make a mess/holes to find out how bad it is
