Well managed to work on the car a bit more today.
Monday I went and had a good look at my donar car out at my dad's and was excited to see that I could use a section of the firewall in behind where the heater core goes to replace what I need to on the Project.
So out came the cut off saw and grinder again, and I removed some more of the bad. Now I can get what need from the donar car and weld it into place, then I can concentrate on fixing the toe board section and get the frame mount reinstaled.
If it wasn't for the accident, (before I got it) none of this would be necessary