Dylan and I recommend using First Light Travel to plan lodging arrangments and activities with. YOU DON'T PAY THEM for their assistance. They have over 13,000 local vendors in NZ and Australia and they get paid by local vendors. They are amazing. They will even schedule a phone call to be able to help you get exactly what you need/want on a specific budget, and the call is out of their pocket, not yours.
Human Catapult
Christchurch to Greymouth train through the mountains