Since I'm not working on the script for the time being, I though it'd be helpful to start putting together some visual reference. For the time being I'm only going to think about the 'world', as I'm still undecided about how to approach the characters. There are only five major environments in the story:
Downstairs Hallway and Stairs
The Street Outside
However- the time of day changes, and it would be interesting of the environment transformed with the mood and events of the story. So really, it's those five environment's, multiplied by two or three, roughly.
Though it doesn't have an exact date, with the references to British India, we know the the story is set near enough when Jacobs wrote it - the early 1900's. The White's are a typical middle-class family living in a typical Victorian country house (The story was written in Edwardian times but house presumably isn't a new build. However the decoration of the interior would contain elements of Edwardian style). They are not hugely wealthy, but Herbert seems to earn enough that they are able to live comfortably. With these facts in mind in gives me a definite style of architecture and ornament to shoot for...