Could it be possible that when Luke went to look for the first Jedi Temple he crashed landed on Anch-To with no means of contacting anyone? Notice the underwater X-Wing in this Topps card: https://i.imgur.com/qAslnbf.png. He probably had no parts to repair it and if he tried to reach out to Leia with the force then Snoke could block it out. In the Aftermath novels she claims something dark was surrounding her unborn son, it could be likely that the dark force that Snoke was surrounding Leia/Ben with was also blocking Leia’s force abilities. Leia feeling Han’s death in TFA could be explained because of Snoke worrying about Starkiller Base imploding and not focusing attention to Leia. After all, Snoke’s plan has been about keeping Luke out of the fight so removing his force connection to his sister would be a priority. Snoke does not know where Luke is but has managed to tear apart the connections to his family. Luke hasn’t been hiding but has instead been trapped on Anch-To. Rey and the Falcon is his way out, but since he has been living here for 2-3 years and learned a great deal about how he was trained incorrectly as a Jedi due to the ancient books he finds on the planet could be why he is reluctant to leave as he has given up hope for Ben and his abilities in this time. The whole “Map to Luke” could and has been explained more as a map to Anch-To using Imperial records and would explain that Luke didn’t leave a map since in this theory he was trapped there with no way back. It may make Luke look a little silly being that he went so far away without a backup plan to get back instead of him abandoning his family and friends in the wake of Ben becoming Kylo Ren. But then again, Luke has always been a little bit silly with his actions (ex. throwing his lightsaber away in the finale to ROTJ) so it fits his character.

Thoughts?