That's pretty good, but I want the player to be able to put things anywhere in the house, where in that script it has specific places that you can put furniture.
You can change an event's location on the map using $game_map.events[n].x = v1 and $game_map.events[n].y = v2, where n is an Event's ID and v1/v2 are any values you please. I think events' locations reset each time you visit the map, so you'd probably need to remember where the player wants them and set the furniture's location accordingly, then fade in the screen.
In practice this would be fairly complicated (especially if you're worried about furniture overlapping, etc.), but it's doable.
The easier way if you have specific
places where you are allowed
to put furniture, and can only put one piece of furniture in a single spot at a single time, is to have invisible events in that spot with all the different possible furniture that can go there, and set a variable when the player chooses to put a certain piece of furniture in spot n. In the event that corresponds to spot n, just make a page for each possible type of furniture that can go there, and have that page require that the variable is (#)
or higher. It'll take a while to set up, but it's relatively clean and simple.