I know how you feel. I have been going through same thing. I think my 85 300D may be worse. I have been goinf between options of selling as-is, having shop do structural only and me doing others with rivets and bondo and having shop do all welding and me do finishing and putting everything back together.
Called shop today to see if they still wanted to do it. It will cost me ~$3k incl my own work and materials. But in my case engine only has 60k miles since rebuild and exterior/interior are cosmetically good.
I need repairs in these locations:
Both inner rear wheel wells front and back inside of arch (4 places)
Both front floor pans at door sills
Front of both rockers
firewall to cabin wall seam
several other smaller holes and surface rust
No economics in doing repairs. But car is too good to trash.
Some pics to cheer you up:
