http://www.tranzscenic.co.nz/services/alpine.aspx

2. I believe the township is Arthur's Pass. Yes, as you mentioned and as the name implies, it's a location for further exploring around the area nearby.

If you've the time, I'd suggest spending a night in Greymouth. Have a nice lunch in a pub in town, people watch - some real interesting characters there...!

The next morning (relatively early start), drive north to Punakaiki. Have breakfast there, they make nice pancakes there. However, the real attraction is 'Pancake Rocks'. Some really interesting rock formations and blowholes. Then, drive back to Greymouth for the train back to Christchurch.

http://www.punakaiki.co.nz/

P.S. If you're to visit the West Coast, bring wet weather gear.