Do I need to sand this whole thing down!

I always use paint stripper on the panels. then scuff and shoot with self etching primer. sanding just destroys the integrity of the sheet metal and causes heat. Just put tape around all body openings and sand only the edges when done with the stripper. steel wool makes them look like new panels. and you will see where others sanded through before.

and even though the quarters were rust free on the outside you would not believe what the inside looked like. also found a couple of tools. Raplaced all lowers as you can see on the pics.