Never use a flash to create a virtual tour! You could never get the exposure to match and it would look awful.
I am a Canon man and use a 5D mkIII so can only speak from my experience. You can set your aperture to around 5.6 and if the room is empty then you can take the shutter speed right down to 1-2 seconds as long as you are using a remote shutter release. ISO of 1000? It depends on your camera and I'd have a try at home first to see how much noise the different ISO levels give.
Hope that helps and please don't use a flash.