It sort of depends on if you plan to do it the correct way, as in getting off all of the old paint, removing rubber trim, and windows, along with the grill, headlights and tail lights. Sanding with an orbital sander will be your best bet. The only parts I would recommend using paint stripper on would be the hood, front fenders and doors. Doors only if u remove the doors from the truck, then remove everything from the door itself.
If it was spray painted over the factory paint you do not need to get all of the sheet metal down to bare metal. You just need to remove all of the spray paint, and whatever factory paint is flaking. After that prime what spots are bare metal and block them as best as possible before repainting.
Doing a paint job the correct way is a ton of work, especially for an entire vehicle. And if you plan to change the color of the truck, there is a ton more work there also, unless you plan on having mis-matched door jams, engine bay, the back of the cab, and front of the bed.
