By the second season there was a really consistent floor plan, however, the directors are allowed to use their own artistic license and rearrange the house to fit a particular scene. For example, in "Hurricane Neddy", Lisa's bedroom faces the rear of the house so she can tell Homer, in the back yard, that a hurricane is coming. In "Lisa's Sax" her room faces the front of the house. When her saxophone gets thrown out the window, it lands in the street for cars to run over it. The directors relocated the room so it could happen

I found a website once that had all the floor plans for the houses from dozens of TV shows, including but not limited to the Simpsons. I'm trying to find it again so I see what TV house is most like the house I'm currently buying.