DISCLAIMER: This is for fun. I tried to think of the least expected theory I could think of. Now I will defend it.
How? Kylo is not on a mission to find Luke but rather to make sure the Resistance doesn't find Luke. Luke must remain hidden from everyone before Rey finds him, except his trusted nephew Kylo. Not even Leia or Han know that Snoke and Luke are one. Snoke is simply a projected image used by Luke. Luke has gone into hiding not to become a greater Jedi Master but to become a secret Sith.
Why? So Luke can establish an Empire the way Palpatine did, using Kylo the way Palpatine used Vader. Luke wants Rey for his apprentice but must first fill her with darkness, so he abandons her and then leads her to him to be trained as a Jedi before training her to be a Sith. Luke plans to lead Rey to the Dark Side by having her kill Kylo and then revealing how she was orchestrated to do it. He will claim its for the greater good and maybe that he is actually Gray and not Dark Side and together they will rule the Galaxy the way Luke would have with Vader. Little does he know that Rey has secretly trained Finn in the ways of the Jedi and his training is finished by the ghost of Anakin Skywalker.
Rey will become Luke's apprentice, but Finn will bring her back to the Light Side of The Force. Together Finn and Rey challenge Luke and defeat him.
All of the stupid coincidences and magical happenings that guide Rey and Finn in TFA may not be bad writing or some new ridiculous version of The Force. It could be Anakin guiding them. Anakin has appeared in all 6 Lucas films and may be in Episode 7, only in an invisible role. Even Han said, "That not how The Force works!"
How did Kylo come to own Vader's helmet when Luke burned it on Endor? Because Luke kept it and gave it to Ben Solo, secretly training him to become his Sith apprentice.
Enjoy this. I hope somehow it is true and I don't care if it far-fetched. I'm simply proving that you can speculate on anything.