It may just be me, and in the pic it is hard to tell, but the framerail appears bent upward through floor pan. I have seen leaf springs do this through the trunk, but not the front rails? maybe it's just the photo. Other than the missing dash, I would be very happy to take on this project, replacing floor pans is expected.
What I'm seeing is if you zoom in on the picture and look closely, you can see that the frame rail isn't bent up, the rusted floor pan hanging down gives it that appearance.