@waldron I just implemented board switching in my game last night! What I did was define each board in an array, with a sub-array containing all of the sprite definitions for that level. By "definitions", I mean the X and Y coordinates of each sprite, the type (such as "teleporter"), and (for teleporters) the destination board and X-Y coordinates, for when the player touches the teleporter.
I have a function called "switchMap()", which grabs the appropriate board element, loops through the definitions for that stage, and populates the level. It does this by creating and adding sprites to an "actors" array, mapping over the properties from the definition to the sprite (so the teleporter sprite will have properties like "targetX", "targetY", "targetBoard", etc.).
This all makes my "draw()" function trivial; it just loops through the "actors" array and draws each sprite according to the properties. Adding a new element to a board takes like ten seconds: just copy and paste an array entry in the board's "definitions" sub-array. Done!
In my main game loop where I'm checking for sprite collisions, if the 'currentSprite.type == "teleporter"', I call my "switchMap()" function, which unloads the current map, loads the "sprite.targetBoard" one, resets the player's X and Y coordinates to "sprite.targetX / sprite.targetY", and boom-- the player is now on the new map, in the correct spot.
I even have "switchMap()" switch the background music to the correct song, which I have in a property in my "boards" array. I have a working transition between a city "overworld" and a sewer "dungeon", and it was really gratifying the first time I could leap between the two at will.
Hope that helps at least somewhat!