How's your trunk? Your inner & outer wheel house are probably toast too. To get the LH rocker off I had to remove the entire LH cowl so it's not worth trying to save. The inner rocker attaches to the firewall and between the LH cowl.
Have you stripped the car? Taking the cowl out buggers the firewall and if your dash is kaput then your upper cowl is probably done as well.
I also had to install a LH lower inside qtr patch panel. It rusted away from rocker and outer wheel house.
The only reason to do this restoration is for the love of the car because we will not get our time & money out of it.
I will assemble a bunch of pics of what I've done thus far. I am trying to attach the outer LH rocker cowl first.
Do you intend to buy the $2800 full floor & trunk pan together? I have plans for a body frame cart so we can align everything given the fact that most of it is being replaced (see attached).