On our 64 we did paint the interior and firewall first to get the cab back on the chassis and the truck running / rolling again- then we epoxy primed all body panels and assembled to check for fit and smooth out panels- and to be sure they were somewhat flush with each other. Next step is disassembly ( again) and shooting color on panels seperatly then reassemble everything. that's how we planned it and the blankets and taping for corners will certainly be done when we reassemble our painted parts...
