Glad to see you're back on the '57 and we can see some updates! That's going to be a huge amount of work to save the body, but I think it's worth it. Not sure how I'd approach the rockers and floors myself? But my space and equipment is limited, so I'd probably choose to do it in smaller pieces.
Your '57 actually has less rust than my '39 had when I bought it. So it's very doable with some time, and elbow grease!