Had some good weather (and some time), so more progress. All of the destruction variety. The passenger seat took some finagling, but I was able to remove it normally. The drivers seat was welded to the rails, though, so it needed to be cut free. I'll need to keep an eye out for a new seat frame to fit the chassis rails, and I will likely put some seats with better side bolstering in on the replacement frame. As I was hacking up the driver's seat mounts, I noticed a little bit of green shag carpet on the floor under the seat. A bit of an odd find. Once the seat was out, the source was obvious. It appears someone had used carpet remnants as seat padding at some point.
Anyway, once I had access to the whole floor, I was able to get a better idea of the situation. The driver's floorpan was definitely trashed, and the passenger side was better, but still pretty wasted. The aluminum skidplate was riveted and bolted to what was left of the pan, and in the passenger side's case, to another sheet of aluminum on the rear floorpan. We unbolted every bolt we could find, then drilled out the rivets on the passenger side, pulled the upper aluminum sheet, and ended up with this:
There were quite a few more rivets on the driver's side, and my 3/16" drill bit was about destroyed at this point, so I attacked the driver's pan with a sawzall, in order to fully remove the skidplate. After inhaling rust, and dirt from goodness knows how many rallycross venues, it looks like this:
Due to space limitations, I am going to try a method of replacing the pans that doesn't involve removing the body. Before that, though, I still have a lot of cutting, grinding, chiseling, and whizz-wheeling to do.
One very positive outcome of this weekend's work - despite there being spray foam stuck between it and the skidplate, the chassis is in excellent shape. No need to do any repair work there, should get by with replacing the pans, and doing some limited work on the body.