Going down to bare metal - Automotive paint stripper. Sit back and watch it bubble

+1 on the paint stripper! Get "Aircraft" stripper and do one section at a time (right rear, rear center, left rear, ect.). When you finish stripping each section, wash it good, let it dry (I use a electric blower to speed up the process), sand it good with 80 grit, wipe with denatured alcohal, and spray with epoxy primer. When the whole car is in epoxy primer, you can start taking out the dents and dings and move on to more epoxy priming and block sanding. This process is slow but if you just work on your car when you can like me, you will make steady progress. Good luck!

Yes the klean strip aircraft stripper works great.
I must emphasize though, make sure to do a thorough flushing of the bodywork with clean fresh water when you're done. I've had to replace wing spars that were turned to white powder in areas where this stripper was not properly flushed and neutralized. It is corrosive.

For what its worth, I sand cars 5-6 hours a day in an auto body shop , and I just finished stripping my car, redoing the bodywork, replacing nearly the whole front clip of my body and repainting it, so I feel you pain immensely

When we have to strip stuff at my shop, we us the the klean strip aircraft stripper that RoyBatty and others reference. THE EASIEST way to go. But make sure to wear gloves, and even a charcoal filter mask (like $30 at home depot) that stuff is toxic as heck! However, when I stripped my car all the way down, I used a SINGLE action sander (more or less a grinder) with a 7 or 8 inch sanding pad. I used 80 grit abrasive sandpaper from 3M. Granted I have alot of experience but even with the 3 paint jobs on my car, and some deep filler spots I was able to strip the whole thing in probably 30 or 35 hours.

An orbital sander is wayyy to slow trust me, and I bought a cheap harbor freight vertical sander(single action) for $40. Just remember, you then need to sand back over with 80grit on an orbital to get rid of all those straight line scratches a grinders makes

If I could redo it id have it media blasted because I don't think it'd cost much more. Good luck to you!!

Another way to go is Dustless Blasting, it uses water instead of air to deliver the media and has a wide range of benefits. First the media stays in basically one spot and doesn't go air born. If you're using Soda its PH neutral and no worries on having to cleanup. It doesn't have the issues of panel warpage line air blasters as the water acts as a cooling agent. It uses less media then traditional air blasting and if you also have them add a rust inhibitor into the water that will prevent flash rusting and give you a few days to work the metal where it needs it before having to go into primer. In the end the cost almost outweighs the traditional methods like sanding or liquid paint shippers that are a nightmare and make a disgusting mess! Ask me how I know, haha...