That is actually the exact use case that I originally built Storyteller for! I wanted to listen to my books on long runs, and then switch to reading when I got back.

The Storyteller mobile apps have great support for this, I think. They have fully fledged audiobook players and ebook readers, and you can switch between the two with one tap. And then of course you can also double tap on a sentence and start playing from there, with the app highlighting the currently read sentence.