I finished it late last night. Blah.
There wasn't a great deal of information that isn't already available (obviously that probably wasn't the case in the late 1970s). Pretty much re-summarizes the events of the books while adding in a few tidbits of outside information from contemporary newspapers or diaries. Still not as interesting as one might hope.
Zochert seems to take for granted how Laura must have felt in certain circumstances, which I found annoying. And my lord did he hammer home the "holy crap their lives were harsh!" in the first years after Laura and Almanzo were married. But not by actual description or relation of events, just by saying "OMG it was soooo hard" over and over again.
There is very little at all about Rose. Next to nothing about life after the books in general, really.
Definitely no bodice ripping.