Any idea how to adapt this for a slow cooker?

Easy peasy. Just follow the directions except place the mole in your slow cooker, pork on top and give it a stir, cook on low until pork is tender. You might want to reduce the coffee by 50% because slow cookers create liquid. So, you should probably make the coffee a little stronger since the slow cooker liquid will dilute it. I think this will work great in a slow cooker.