Dear Harry,

  Something I do (not perfect) is taking the digital Devanagari text and input it to Google Translate set to Nepali. The phinetic transcription yields tolerable IAST text with some quirks that can be easily fixed with the "replace all" feature on Microsoft Word vel sim. (e.g. ē -> e). As I said, not perfect, but good enough. I hope this helps!

  namaskaromi,

  Diego