Once the lose thin stuff was cleared out a toddler could of nestled in there.
S10 4x4 Pick Up by George Kachadoorian | Photobucket
It's all foam filled now.
I think once the rust starts to become an aerodynamic issue something as radical as this must be done. It is not as radical as that guy in Russia making a whole car out of this method, but it is transforming, and can be part of an Metamorphosis .