Incidentally, I sure hope there's a few more intermediate stations built than are marked on that map. Quite a few big gaps IMO.
A rough Google maps estimate says its 26-27km from Sunshine to Broadmeadows by Melbourne Airport. In that space there is a lot of room for more stops. East Keilor, Airport West and Westmeadows could be good candidates based on the current Albion-Jacana freight line. This assumes that you go up Airport drive only on the clockwise run. If you used Airport Drive on both (which is probably less efficient) you could have stops at Gowanbrae or Gladstone Park. These areas would benefit a lot from a station but first the Government needs to stumble across the idea that's been tossed up here that there is a massive void in the west