I see one more requirement for the pdf program. It has to be able to take what is within the margins of the Mathcad worksheet and put it into its own column margins. That could be hard to find. PDF Creator can put two pages on one sheet, but it includes the wide margin as part of the page, not just the text portion.
If you have a publisher in mind, maybe they have a program that can take your single narrow column and reformat it to a two column layout?