Kevin Hearne wrote a novel that is considered cannon which takes place between A New Hope and Empire Strikes Back. Luke is all alone and trying to figure out how to train himself as a Jedi without having Ben or anyone else to help. He does not know about Yoda yet and can barely use the force.
In this novel he is escorting an asset that can break imperial codes. The plot is simple but it does flesh out Luke quite a bit. There are a few moments that are important in Lukes training that probably offer hints about Rey. Luke has had no training and is not always successful at this point with the force. It will take him quite a bit of practice before he will be able to summon his lightsaber in the ice cave on Hoth. Something Rey could do instantly. Hmmmmm.
This book was good I rate it 3 1/2 stars.