I think a rust removal forum would be a great asset! As you have discovered, there are a number of ways to attack the problem. One word of caution, sand blasting with the wrong technique will warp sheet metal so make sure who ever does it knows what they are doing. A lot of shops use things like soda for blasting.
I tried the electrolysis route for some large fenders and it was helpful. I didn't get them all the way down to bare metal but I got a lot off. I used a little wading pool which was quite disposable after.
For areas under the dash i bought a flexible drive to on the drill and reach places where the drill doesn't fit.
In general you will find that one method doesn't fit all your needs. Also you will need to take most of the sheet metal apart to do the job. If money was no object, a professional chemical stripper with the tanks can do the best job, in my opinion. I used them for my doors but I saw complete body assemblies in there being dipped.
