Think I'm screwed

Oh thank God. I recently located a 73 dart swinger parts car at a pull and pay. Would a suitable replacement be on it? And maybe even useable floorboards?

Look under it and see if it is rotted out like yours. If not fire up the battery powered sawsall.

Edit
Strip all the good Parts off of it that you possibly can. You can buy them from that you pull it cheaper than you can buy them from a Mopar person. In most cases at is.