Thanks for the kind words. :) I'm glad they're helpful.
You are absolutely on the right path to solving your problem. All you need to do is make new "teleportation tiles". Basically, if the player tries to move onto a specific teleportation tile, instead of doing something like opening a door, or getting a key, it would change the player's X and Y coordinates to a new location inside the house (the separate part of the map). And then in the house, you would have another teleportation tile whose job it would be to send you back to the coordinates back out in the world. I hope that makes sense! Let me know if you would like more explanation.