Cascade Saddle route for experienced day-hiker?

Hey folks, After graduating college this December, I'll be leaving my home in Minnesota to explore NZ for the month of January. I'd love to hit Mt. Aspiring National Park and am thinking about doing PART of the Cascade Saddle route. The tentative plan is to do it in 3 days/two nights @ Aspiring Hut: For Day 1, hike to hut and stay the night, use Day 2 to trek up to the saddle and back down to the hut to spend another night, and head back to trailhead on Day 3. I'm an experienced day hiker and grew up hiking in the Canadian Rockies and the U.S National Parks. I'm comfortable hiking 10-20 miles a day with with a large pack, doing some serious scrambling and route-finding, I've got tons of experience at elevations (and very exposed routes) over 12,000 ft (3,700 m), I know how to monitor the weather and when to turn back, set up an emergency shelter, etc. I'm also done a ton of camping. Problem is, I've only ever hiked and camped independently of one another; I've never actually done a multi-day hike. I'm thinking NZ might b a good opportunity to marry the two and actually do my first overnight hike--would this portion of the Cascade Saddle route be a safe and feasible opportunity? I've got six months to prepare--as such, I plan to learn a TON about backcountry camping, make sure I have all the right gear, get a lot of practice in, etc. If my brother doesn't come with me to NZ (also an experienced hiker / marathon runner), I plan to make arrangements to find a buddy, as it sounds like this route isn't something you want to do alone. Thank you SO much for your input and feedback!!