Man, you asked the mother of all time vampire questions ...
OCR scanning will get it done the fastest ... but with mixed results based on the quality of the pages ... I mean where do S's and 5's begin and end on 10 point printing? throw some text up in what the font and see what comes out ... same thing with an ocr scan.
Just going to have to retype and tell the customer with that much text you have to charge an hourly fee to typeset. ... only sure way to get it done right.