Working to learn pico-8 from this tutorial, the game game i have in mind is one where the player enters several houses. I’m thinking I’d wall off parts of the map and draw the interiors there, then it should be possible to instantly transport the player over to that part of the map if he hits a door, (or rather the sprite on top of the door to make him hit the up arrow). Could you point me to any resources on how to do that?

Even though my ambitions are greater than my abilities right now I’m having so much fun with this,  enjoying your instructional vids a lot, they are very concise and clear so thanks a bundle for that.

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.