The outside of the Bates house is extremely small. The front porch is no more than 10 feet wide, and the whole house less than 25 feet wide, and perhaps 30 feet deep. (This is about the size of 4 of their hotel rooms.) And yet many of the rooms inside the house are much larger than this. The master bedroom alone is at least 30'x30', and it is just one room on the upper hallway, that includes a vaulted stairway.
The audio for Norma's car is always that of a diesel engine but the car, a Mercedes 280 SE 4.5, is a gasoline powered V8.