Had a great stay at Susan's and the room felt bright and cheerful. By the second day, I didn't really need a map to get from Upton Park station back to her place so that was good (I recommend that you download CityMapper app to get around). The Central line is always TOO crowded and I'm not sure I'd stay anywhere along Central tube line, so it's great that you can take District or Hammersmity&City straight to Upton Park. The surrounding area felt safe but of course use your judgment; some nights there's people hanging outside a bar near Upton Park station.