I've read stories of cars being ruined, even by "professional" media blasters. If the job is turned over to the "new guy" that day, you could have trouble. On the other hand, nothing cleans the paint and rust out like blasting. Glass bead, plastic bead or walnut shell will remove paint. Something more aggressive and risky is required for rust. A lot will depend on being absolutely sure the person who does the job for you knows how to do this job without damage. The shop that cleans tractors is not the place to go.

Media does not work well on soft stuff, so if you plan to take off undercoat and sound deadening, it will be better to remove this chemically.

When you go looking for rust, pay close attention to the front and rear windows, floors, the lower dash and cowl area and behind front and rear wheels. After inspection, you may chose to drive the car for a while first, because once you get into repairing that much rust, its going to be a long time.

You ask about panels repair vs replacement. If you can cut out rusted sections and weld in patches, you will be better off repairing than attempting to make repro panels fit. The money you would spend on new panels, you can spend on a nice MIG welder and teach yourself. I think it could actually be less work unless the original panels are totally shot. The repro parts are not the correct shape, correct length, or correct gauge. Some are better than others. It takes a lot of work to get them looking okay and it still requires welding skills to fix them and to install them. In fact, I would say you cannot restore this car without owning a welder unless you fix it by writing checks.

Good luck with your project Ron and welcome to FGF.