All kinds of great advice here - I'll try to be specific
Have 6 nights, flying in and out of Queenstown (Canadians) in mid September.
We'll be renting a car. Is it a better idea to drive to Milford Sound, or take a bus tour? Thinking about a few nights in Te Anau; is that a better starting point for Milford Sound? Definitely want to do the boat on the fjord. And Franz Josef - is that a day trip or is it recommended to stay overnight? Also want to see the wineries. Are they all close enough for day trips out of Queenstown, or are they destinations themselves? Main interests are seeing the glaciers and scenery, wildlife and wine/great dining. Thanks

To address your three concerns:

Milford: If you spend 2 nights in Te Anau, it's a wonderful self-drive daytrip to catch a cruise and return for the night. It's really too far from Queenstown to do yourself. That leaves you with tours. Either a coach/cruise/coach tour that will be 13 hours. Or a coach/cruise/fly that leaves you a couple of hours left for relaxing or more Queenstown activities -- this is the most expensive, but gives you a different perspective of the area from the air. And the coach tour does all their stops on the way TO Milford, allowing passengers to sleep on the way back. Then there is the fly/cruise/fly approach for those really tight on time.

Glaciers: With stops for short walks to the many waterfalls along Haast Pass, and beachside stops, it is a 6-7 hour journey from Queenstown to Fox or Franz Josef. You would certainly want to spend a day there to walk to the glacier faces, Lake Matheson, or do a heli-hike. Then devote another day of traveling back to Queenstown. So that's 3 days of your trip. Is it worth it to you?

Wineries: Chard Farm and Amisfield are half an hour from Queenstown. More wineries along Gibbston Valley. Drive 45 minutes and you have another crop of wineries in Cromwell and Banockburn. Perfectly do-able for a day. We rented bicycles in Arrowtown and rode along the Arrow River. We got a chance to pause a bit to watch the bungy jumpers and proceeded on to Chard Farm to wine taste and have our picnic lunch. When done, we called the bike hire company to pick us up. It doesn't get any better than that! Very affordable as well. Mid-September might not be as nice as when we did it end of February, but you might want to keep it in mind. Cowa has a downloadable winery map here: http://www.cowa.org.nz/wine-maps.html

The drive along Milford Road to Milford Sound is beautiful, but in mid-September, there's still a possibility of winterlike conditions, ice, frost, and avalanches. You wouldn't want to drive in and get stuck. You won't know until you get here. Please read these links:
http://www.doc.govt.nz/parks-and-rec...s-for-drivers/
https://www.nzta.govt.nz/projects/sh94-milford-road/

The round-trip all-day coach trip with scenic stops plus cruise from Queenstown adds would be almost 13 hours, the coach trip from Te Anau would be about 4 hours shorter, but you'd have to spend a couple of nights in Te Anau. See this link for one of the many companies offering coach tours to Milford Sound:
https://www.realjourneys.co.nz/en/ex...cenic-cruises/

If you can afford it, you can also opt for the coach-cruise-scenic flight option, which would save time and probably be gorgeous. Note the flight doesn't take off if the conditions are not perfect, in which case you'd have to return by coach. (My scenic flight from Milford was cancelled due to bad weather).

Te Anau has attractions of its own, and the drive from Te Anau to Queentown is beautiful (though not as beautiful as Milford Road).

You should overnight in Franz Josef, In fact, two nights would be better because it will take you about 5.5 to 6 hours to drive from Queenstown to Franz Josef. This is not an easy drive, and it is not one to rush through, you'll want to stop for photos, short walks perhaps. See the drive distance calculator:
http://www.aatravel.co.nz/main/time-...calculator.php

Consider spending a night or two in Wanaka instead of Queenstown because it would shave some time off your drive to FJ. I don't think you'd regret it, as Wanaka is lovely with excellent walks and winery with fantastic views (Rippon). Or is your hotel already booked?

Six nights is not many, and there are many things to do in and around Queenstown. As you asked about the nearby wineries. Amisfield Winery and Bistro is only about a 10 minute drive from Queeenstown's CBD near the turn for Arrowtown (at Lake Hayes Road). http://www.amisfield.co.nz/
Their "Trust the Chef" dinner can be great.

Gibbston Valley wine region is a bit beyond Amisfield. Gibbston Valley is home to Chard Farm, Peregrine, Gibbston Valley Wines, Brennan's, Mt. Rosa, etc. It's a small wine region but very pretty and easy to get to from Q'town. Here's a map for it:
http://www.centralotagopinot.co.nz/d..._02.pdfCentral Otago wineries overview:
http://www.nzwine.com/regions/central-otago/

Gibbston Valley is also home to A.J. Hackett's Kawarau Bridge Bungy, NZ's first bungy jump. Even if you don't feel like jumping, you might want to have a look, it's almost across the road from the road to Chard Farm Winery.
http://www.bungy.co.nz/kawarau-bungy-centre

Some of Central Otago's most highly regarded wineries are in Cromwell and Bannockburn, which is about 10 minutes from Cromwell. Cromwell is beyond Gibbston Valley via Kawarau Gorge Road (part of State Highway 6). So another 20 to 30 minutes of driving along a beautiful but narrow, twisty and busy road. It may or may not be worth it for you. But if you want more info about Cromwell/Bannockburn wineries, just ask.

Personally, I consider Cromwell and Bannockburn to be a destination in and of itself and prefer to overnight if visiting many wineries (it's also safer). But I live in Dunedin, so it's also a practical place to stop between Queenstown and Dunedin.

There's so much else to do around Queenstown. I consider a day trip (or half-day trip) to Glenorchy a must. The Skippers Canyon tour is also scenic and interesting. Many people enjoy trip across Lake Wakitipu. And you might want to visit historic Arrowtown. Queenstown itself has the Skyline Gondola and a lovely botanic garden.

You might want to read about State Highway 6:
https://en.wikipedia.org/wiki/New_Ze...tate_Highway_6

You'll have some tough choices to make on how you'd like to spend your 6 days in and around Q'town.
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<<We'll be renting a car. Is it a better idea to drive to Milford Sound, or take a bus tour?>>

I much, much prefer self-drive. Too much for a day though, no matter how you do it - 13 hours is 13 hours no matter who drives...and Sept weather can be very iffy.

You've got about 11 hours of daylight to work with in September, so that means at least two hours in the dark. Can't see scenery in the dark! If you can swing it, look into the drive/fly option, but do be aware Milford weather is pretty fickle, which can throw a spanner in the works, especially on a tight schedule..

<<Thinking about a few nights in Te Anau; is that a better starting point for Milford Sound?>>

It would be for me. Milford needs a full day, inclusive of walks along the way, and staying in Te Anau gives you the opportunity to make a more leisurely drive than from QT. Four hours less of driving. Head start on the bus tours (not that Sept is particularly problematic, unless of course Milford Road has been closed, then all the buses sort of clump up when it re-opens- been there, done that).

<<And Franz Josef - is that a day trip or is it recommended to stay overnight?>>

Definitely NOT a day trip - at least a six hour drive each way, plus you'd need at least a full day there, and cross your fingers for good weather. So, there goes three days of your six days.

<<Main interests are seeing the glaciers and scenery, wildlife and wine/great dining.>>

Plenty of scenery and great dining in QT. Plenty to do in the vicinity to fill your time w/o having to spend your entire holiday in the car. I suggest you visit Milford (staying in Te Anau) and then spend the remainder of your time in the QT area. From there you can visit Glenorchy, Wanaka, Arrowtown and still have a relatively relaxing holiday, not a marathon driving trip.

I failed to read the previous responses until now, but seems we have a consensus!

<<Personally, I consider Cromwell and Bannockburn to be a destination in and of itself>>

Me too, have spent multiple nights in Cromwell each time on several trips. Pinot Noir and dry Riesling nirvana.

Dundebdav, sorry about all my previous typos, I was on my way out the door.

Regarding wildlife you might see along Milford Road, on Milford Sound, and near Glenorchy, look at responses to this earlier post:
http://www.fodors.com/community/aust...s-424857-2.cfm
You can see also glow worms on a tour from Te Anau. Te Anau also has a wildlife centre with rare endemic birds in enclosures. Some of the birds have been injured, others are part of a captive breeding program.
http://www.doc.govt.nz/teanaubirdsanctuary
You'd also have a chance to see captive kiwis in Queenstown or Franz Josef.
http://kiwibird.co.nz/kiwi/
http://www.wildkiwi.co.nz/

I wanted to add that part of the road between Queenstown (or Wanaka) to Franz Josef (or Fox) can also be subject to wild weather in September, specifically, the section through Haast Pass. September is the second wettest month for this area. In September 2013, there was a major slip at Diana Falls, near the Gates of Haast, that brought down 40,000 cubic metres of rock. On the same night another slip nearby killed two Canadian tourists. It was a great tragedy. The area has since been reinforced with the best rockfall protection system in Australasia.
http://www.radionz.co.nz/news/region...all-protection
However, inclement weather can still lead to closures, as you can read about in the article from Sept. 5, 2015:
http://www.odt.co.nz/news/dunedin/35...way-metservice

Melnq8, multiple nights in Cromwell/Bannockburn—even better, more thorough! I agree about the pinot noirs and rieslings, but also must recommend the dry rosés (Akarua, Terra Sancta, Wooing Tree), and sparkling wines (Quartz Reef, Akarua). Another plus is being able to taste (and/or buy) wines impossible to find in the stores. Nice restaurants at Mt. Difficulty, Carrick and Wild Earth, too.

Diamantina -

Your post was a sobering reminder that the tragedy in Sept 2013 occurred just two days after my brother and I drove that same route.

My goodness! Thank you all for taking the time with such detailed responses! I have a lot to think about.
I'm thinking that staying in and around Queenstown is our best bet. The west coast and glaciers will have to wait. Milford Te Anau 3 days. Food and drink in Cromwell, Arrowtown Waneka 3 days. Hotels not booked yet, but really want to get that done soon. Weather could certainly affect order in which we do things, but we'll have to chance it.
One question: If we drive ourselves to Milford Sound, we'd like to do the cruise. Does Real Journeys trip go all the way out of the sound to the ocean? Any other tour companies recommended? Thanks again.

Milford Sound is not that large (Doubtful Sound is a lot larger). Have a look at this short description from Jucy Cruize, which is one of the many companies that offers cruises of the sound.

"Milford Sound is the northern most of 14 fiords that make up the spectacular coastline of Fiordland National Park, part of Te Wahipounamu World Heritage Area and our Cruise Milford boat tours travel the 16km length of Milford Sound to the Tasman Sea and back."
I'm sure you'll find this link informative:
http://www.jucycruize.co.nz/useful_s...ord-sound.aspx

Probably won't affect you, as you'll only be around Queenstown for 6 days in mid-Sept., but school holidays start on Sept. 24.

Cromwell sits on Lake Dunstan and is surrounded by orchards and vineyards, not as scenic as Wanaka, Queenstown or Te Anau, nor does it have a wide choice of restaurants, but it is a great base for visiting the wineries of Cromwell and Bannockburn. It also has quite a few moderately priced and inexpensive motels with kitchenettes. You can do a loop from Queenstown to Wanaka to Cromwell then Queenstown again. Have a look at this touring map of New Zealand:
http://www.newzealand.com/travel/library/p23573_23.pdf
Scroll down to the second page and then zoom in on Queenstown.

Use the aforementioned drive distance calculator to figure out your drive times.

Bannockburn is scenic, almost high desertlike, with old gold mining sites. Mt. Difficulty has the best views in Bannockburn, a lovely restaurant, and a friendly, welcoming tasting room:
http://www.mtdifficulty.com/