For example, I have a ready-made scene with the game interface (without locations and the player), when the player enter the game he has one button available in the interface scene - load the location.
When a button is clicked, an HTTP request is sent to the server, after which the location names are returned in JSON format: for example ("load": "locationa.pck"). After that, a child node with location and player "locationa.pck" is added to the interface scene.
And then the gameplay ...
When the conditions for switching to location b are reached, the child node with location "locationa.pck" is deleted in the initial interface scene and a new child node with location "locationb.pck" is added.