Now that I've got a welder I'm starting to work on the driver's side floor.
Last week or so I removed most of the remnants of the replacement floor that the PO welded partially on top of the old floor. I also removed the cross-member, which was almost completely rusted away. I took a careful look at the remainder of the floor and sills on the driver's (left) side, and saw that the PO only did edge-welds, which makes it very easy to grind them away. Last week I also ground down some of the welds on the top of the sill, where the outer and inner sills meet. I realized quickly this was not the right approach.
So tonight, I ground down all the welds on the bottom of the sill (where it meets the floor.) It's a new outer sill, inner sill and sill strengthener piece, but the original floor, I think. All the welds are gone now and the floor has started to separate from the sill, which is what I want.
I then started to remove the radius arm bracket which is quite crusty and rusty (especially near the floor.) I took off the two nuts in the inside of the passenger compartment and started to grind down the edges of the bracket, so I could eventually drill out the spot welds. But, I couldn't get the grinder between the inboard side of the bracket and the transmission/drive shaft hump. So I have to come up with something else.
Last, I tried to remove the rest of the radius arm (behind the heelboard). But, the bolts are too rusted right now. I sprayed some Kroil on them and tried for a while, but gave up. I sprayed more Kroil and cleaned up for the night.