A week in NZ won't get you anywhere
I have not climbed Cook, I have only climbed in NZ in winter. But in the absence of any other input here, some points based on what friends and colleagues have said:
- this is assuming you try the 'normal' Linda Glacier route from Plateau Hut
- it's a very
long day, maybe 12-17hrs of continuous movement
- with a massive height gain of around 1700m, meaning you will be slowed down slightly by altitude up high, though unlikely to get sick
- the Linda is often very cut up with crevasses, making difficult travel
- especially in Jan-Feb, though this year was better
- the Linda is actually very dangerous in a purely objective sense, with massive seracs poised above the route. They fall. Move fast.
- there is a shelf to traverse up high which requires proficient and confident cramponing, esp in icy conditions
- the summit rocks have fixed pro, but require some basic climbing skills, made harder by big boots, a pack, gloves and exhaustion
- descent of this is via abseil = dangerous
- though the altitude is low, Cook is in NO way comparable to similar 'training' mountains like Rainier or Mont Blanc. You need to know what you are doing and be able to do it yourself, well.
- fitness is important, and don't let people tell you otherwise
- allow at least a week just for Cook, better is 10 days. and this is after you've spent a couple of weeks climbing other peaks in the area (or Mt Aspiring etc).
- you may spent 5 or 6 days stuck in the hut, so take food and books accordingly
- but on the other hand be ready to go the evening you step out of the plane/helo. it's all about the weather and conditions
It is a totally different thing than Aconcagua (which I have climbed). There is little meaningful similarity. Dogs have climbed Aconcagua.
If you have never used axe or crampons and are not being guided - don't do it.
Get down to Blue Lake, out from Guthega, and practice with axe and crampons on the nearby slopes. No need to climb vertical ice. NZ climbing is about moving fast and continuously with proficient footwork and judgement of conditions.
Then maybe try climbing easier peaks from Tasman Saddle or Pioneer Hut. Then think about Cook.