What has he been up to, all these years in between Return of the Jedi and The Force Awakens?
We know one thing for sure: He rescued two very important Force-trees from an Imperial facility, and gave one to Poe Dameron’s mother. (Look, she was married already, and Poe was a couple years old at the time, so no, Luke isn’t Poe’s dad. Fun an idea as that might be.)
He kept the other tree.
Everything else we know, until he appears on screen in The Force Awakens, is either hearsay or “legend.”
The bit in the Aftermath novels about him wanting to retire to a private life as a citizen? That’s Admiral Ackbar’s story.
The bit in Bloodline where Luke and Ben are traipsing about the galaxy together, six years before The Force Awakens? Speculation. Leia hasn’t heard from them in “months,” as I recall, and the last message she’d received was so garbled with radiation interference that she couldn’t tell what they were saying.
What Han says about Luke in The Force Awakens? We trust Han, but was the source of Han’s information trustworthy?
And everything in The Legends of Luke Skywalker? To be taken with a grain of salt.
I’m sifting through the stories and suppositions to put the pieces of this picture together…