quickest way to strip the paint ?

[bootlegger]

Go and buy 4 litres of paint stripper, a box of single edged razor blades and scraper, gloves, mask and a 8 inch strip it disc. The strip it discs sort of looks like shredded plastic and goes onto a disc sander.
Strip as much of the paint off as you can with the paint stripper and then work the rest off with the strip it disc.
As Scotty said make sure you neutralise the stripper with water before you use the disc other wise you will have problems later (especially if you get some on your skin).
the last couple of cars I have done Ive paint/ strip it disced and then had the sandblaster do the door jambs and dust it over. That way he doesnt warp any panels.
Its a lot of work no matter how you tackle it.
I once stripped a 61 LIncoln Continental convertable with one razor blade (and it was full of filler)
BTW it cant be done any way for $50

Whatever you do dont use a normal sanding disc to strip the paint off. It will wreck the panels. I had a customer strip his own car (a Honda S800) to save some money. He totally wrecked the car and added several thousand to the eventual bill.