The beach at wanaka tree is one of the best places to view the sunset, with the beautiful mount aspiring as backdrop

The best view of the lake, period, is from the top of Roys Peak. But that's a very strenuous hike, 5 plus hours to the top and back, with no campsite, although people have been known to pitch their tents, and a hardy few dare to descend by flashlight in order to catch the full sunset. You can also get some gorgeous sunset views by driving along the Wanaka lakeshore to Bremner Bay. From there, the view across the lake to the high peaks of Mt. Aspiring National Park should be great as the sun goes down, this week or any other. It's an expansive view, if not Roys Peak, but allowing you easily to adjust for the position of the setting sun any time of year. I can't speak to what will work best precisely this week, but the lake and the surrounding mountains are on a massive scale, which makes it pretty easy to capture something worthwhile at sunset. And don't discount the view from the shoreline at the Wanaka tree. If you think it would be trite to include the famous willow in your photo, you'd be wrong. It's quite splendid in the foreground of the craggy mountains beyond.

Anywhere on the lakeside would be nice, the sun sets over the mountains and creates a lovely silhouette

If you park on the main car park and face the lake, follow the shoreline as it curves around to the left and you will come to the Wanaka Tree. It stands before a row of very tall Poplar trees which you can see a long way off. The tree looked so beautiful with its Autumnal colours, guess it will be just coming into bud in Spring. If you hire a Kayak, you can paddle right up to it :)