Used Tranzalpine to from Christchurch to Greymouth. Fantastic way to get to the West Coast and the Glacier region.
AM departure will get you to Greymouth at 1pm, with plenty of time to drive/take a coach to Franz Josef or anywhere else on the West Coast before the sunset.
The scenery is stunning (plenty of stops for photos), coffee at the cafe is great. Expert commentary insightful.
What more do you need but relax for the next 4,5 hours? Great value for money!