Major rust repair

[1962 Panel]

Hi everyone, recently I have been researching and contemplating what would be the best way to repair the rust on my '62 4x4 panel truck. The rot is pretty extensive in the firewall/ floor/ kick panel areas and the cab mounts have long since disappeared leaving the body to be supported by the bellhousing The easiest way to remedy this would probably be to get a clean body but being that it is a panel truck and not easy to find, that would likely be the most expensive option as well. I was perusing craigslist the other day and came across a pretty clean 64ish cab that had a tree fall on it and crush the roof. Upon seeing this I got the idea to cut out the ENTIRE floor portion, lower firewall, and kick panel area all the way to the top of the fresh air vent and attempt to graft it to the panel truck body. Any thoughts? Anyone done it before? I'm no expert when it comes to welding and fabrication which is why I am apprehensive to just patch up what I have because there are a lot of places that they don't even make patch panels for Any input would be much appreciated!