It looks like when this book is released later this year it may answer my question. This was posted on Unbound Worlds:
The Legends of Luke Skywalker (10/31)
by Ken Liu
Details are scarce on this Journey to Star Wars: The Last Jedi novel. Liu, who you probably know as the author of The Grace of Kings, announced the book on his blog a few days ago. Given the degree of secrecy surrounding the title, I’m guessing that we might learn a little more about what the great Jedi Master was up during his self-imposed exile. Honestly, though, I don’t know any more about it than you do.