If you are keen to see what is involved in a complete floorpan replacement and other rust repairs on a Mustang have a look at this series. This is the first in the series but subscribe and watch through them all. It is still a work in progress. Note turn the sound off to make these kid friendly as Pete tends to be pretty colourful.
https://www.youtube.com/watch?v=S5JZ1m1undo
