OK lets see...
Just the one place to stay, awesome setting in the beech forest 5mins stroll from the bottom tow. You're either in 6-bunk rooms, or for about $15 more per person can have a double room (either double bed or double plus a bunk for the kids). Highly recommend the double rooms if you're coming as a couple. Everyone eats/lives/drinks (mostly drinks) together in the main lodge. The bar goes off, especially after a powder day.
No way to get there from Cass AFAIK. I'd forget the train. I'm pretty sure you can find a commercial operator to give you a return trip from Christchurch (4WD Hi-Ace type of thing). There might be a phone number or link from the CVSC website. I could find out for you if not. Some people rent a car in Chch but I'm not sure its worth the hassle and it just sits in the carpark costing you money all week.
No I don't live there :-( I live in Christchurch. Spent most of a season there once tho' which was pretty cool.
A day at Porters on the way home could be good - maybe wait til you get here and see what condx are like. If Craigieburn is good you wont want to leave, trust me on this. And Porters can be struggling for cover sometimes. You can also ski Broken River from Craigieburn - hiking required is about 10 mins on the way over and 40 mins on the way back. There will probably be other people doing this during the week, I recommend it. The two fields are promoting themselves as one large backcountry area this year. Also you might easily meet someone on the skiweek who is keen to drive to another field for a day.
Ah so you've seen Mt Shut, Coronet Creek, Cardrongo, and The Regrettables. All OK on the right day, but NOTHING like Craigieburn. You are heading in the right direction, grasshopper.
Triple Black Diamond - I might give that one a miss. But I'm sure your skiing will be fine for most of the field - I've seen a few of your postings in here over the last year or so. Most of it is no harder than the Towers or the South Face at Mt Hutt. And there ARE some easy(ish) runs, mostly its the snow conditions that can be tricky - no grooming so you have to be prepared to "enjoy" whatever nature provides. Popular skis are Mod-X, Intuitive 74, R:EX, G3 etc. Quite a lot of helmets too.
Oh, and its opening day tomorrow
Hope that helps, feel free to ask for more info.