Acid dip experience???

Soda blasting won't realy get rid of rust, so it sounds like you'll need two types of blasting. If that's the case your best/easiest way out is taking it to a professional. They'll have the appropriate medium & equipment to do it right. I recently had the undeside, trunk, interior & engine bay soda blasted on a project & it was only about $200--- well worth it, IMO. From what it sounds like, I'd budget about $500 for the job and be happy with that....