NEVER sandblast as sandblasting can generate enough heat to warp your body panels and ruin a good car. Although there are a good assortment of media specifically made for paint stripping on sheetmetal, you will have to pay someone to do it and I still don't really trust it.
Here is a video that might be of interest: https://www.youtube.com/watch?v=vzo7eicjm1U
That is a hand held grinder with a soft backing pad that you apply a "sticky" sandpaper disc. You can get these at your local autobody/ paint supplier or perhaps other places. I have used this myself to strip paint off cars. I don't recall what grit paper to use, but your autobody supplier can certainly recommend the grit. Again, use a little common sense so as not to get the surface too hot by constantly moving and not staying in one place too long. Let the disc do the work and not force or bear down with heavy force on the grinder because you want to speed things up. When the disc clogs up and does not cut very well, replace it, don't try to "stretch it" to save money because you may not be cutting the paint and simply causing friction that heats the surface -which you don't want. You will get a knack for this after a little time doing it.
You will want to wear goggles and a face mask -you don't want to breathe that crap in. It is going to get dusty. Keep this in mind where ever your car is positioned 'cause the grinding dust will cover everything.
Other methods are a DA sander, but you need a compressor. DA will be slower, but works. Chemical paint stripper - but it is messy. And then you have to wash/neutralize it off the panel. Now your panel is wet and subject to rusting quicker if you don't paint/prep it in a timely manner. Personally, never used the chemicals for that reason -too messy.
Bare Metal prep. This has been covered on some other threads. You want an epoxy primer -which has been recommended many times and I have not personally used it. The average red/grey primer is not a sealer. So moisture can penetrate and rust develops under/through the paint. Works just fine for short term coverage, but projects always seem to be long term -at least mine are. You can also use a metal etch primer which I have used. This blog gives you the differences between the two and their applications for use and why. It would appear that the epoxy may be the better option if you need to do bondo work. Again, personally, I don't like to put bondo over anything other than roughed up bare metal, so if I used epoxy or metal etch, I would still cut through it anyway to give the bondo a good bite. Here is the article: Epoxy vs. Self-Etching Primer for Painting Bare Metal | Gearhead Diva
Hopefully you will get more input. I am no expert who does a lot of cars, and haven't stripped or painted a car in about 25 years, but used to when younger and this is how I did them. There may be a better way.