The key to minimizing sleep disruption is to use as little light as possible. Light is your circadian rhythm trigger for wakefulness. Therefore, the best scenario is no light at all. Obviously, for some with less than perfect night vision, moving about in total darkness can result in some pretty nasty bumps and bruises. If you must light your way, use the lowest possible output lighting. A 4 Watt nightlight in the bathroom is usually sufficient.