I have been wanting to save some of the posts here as PDF for future reference. I use Chrome on a pc and I found only one Extension that lets me do it. Its here: https://chrome.google.com/webstore/detail/printwhatyoulike/npgfabafajliaooeicdoahbpoajfmbbe/related
When I choose the column of the post on Google+ and click WIDEN it lets me print out the entire post and comments nicely to PDF.