Taking really thin metal to bare metal is not a good idea unless you know what you are doing. I suggest using a paint stripper and a plastic scraper to remove the paint after the chemical process has lifted it from the metal. Do not sand it with a DA as you could heat up the thin metal and easily warp it.
Unless you plan to do alot of metal work such as adding or removing body lines and or sectioning a panel or if you suspect that there has been severe damage that cannot be seen from the back side so the only option is to take the front side of the panel to bare metal you do not have a reason to take it to bare metal.
My car has been bare for a while, I used to cover it with WD40 to seal and clean it scrubbing it with steel wool and then wiping it down with dry towels. I let the WD40 break down when I was ready to park it and start on the metal work. I found what I was looking for which was some warped panels, heavily filled rear section from a collision and a bad quarter panel replacement.