Where do I start!?!

[Coyote187]

I have a small problem... I need to start work on my 69 camaro and I’m having trouble figuring where to start.
First off here is basic idea of what I want to accomplish. I’m putting a tri 4 bar in the rear; I’m also hanging new quarter panels. Also I’ll need to change out the upper rear panel ECT.
Now with that much body work, will it be best to have the chassis put together first or the other way around? Now the entire trunk floor will be custom built to the new rear clip.
I will be building both a chassis fixture and a rotisserie for this project and I’m not sure here to start