Since I didn't know initially what parts of the floor were still metal and which ones were just undercoating and sound deadening material sandwiched around rust, I ordered both full floor pans and the passenger side rocker panel.
I cut out a decent amount around the pedal, with both the depressions for the pedal and fuel lines collecting sitting water. This is almost fully welded in. I'll take more pictures after it's ground and sealed.
Here's the patch underneath the seat. Only partially welded at this point.
