I've had messages from Boomerangers who are starting to piece together an itinerary of between a week and three weeks, some coming alone and other with wife and some with wife and child(ren).
So many different needs and interests, and so much variety on offer in Australia, so rather than give specific advice to those looking for some pointers, here is some general info you can use to work out what you most want to see.
Sydney
A beautiful city with great beaches, and early March is still great beach weather. The Blue Mountains an hour west are a great sight to see (The Three Sisters etc), as well as walking the harbour foreshore and seeing The Harbour Bridge, Opera House etc. Ferry over the harbour to Manly is great, too.
Golf worth playing:
New South Wales Golf Club (Sydney - MacKenzie/Apperley)
The Lakes (Sydney - Mike Clayton just did a redesign)
Newcastle (90mins north of Sydney - Eric Apperley)
Canberra
While not necessarily a must-see, Canberra is the nation's capital, located roughly halfway between Sydney and Melbourne. It has our parliament house - a kinda cool building, the War Memorial - very interesting, and if kids are with you (or kids at heart) Questacon science centre is a must - lots of fun intereative stuff. Manuka is a great dining area and were you driving between Sydney and Melbourne, it's a sensible place to spend a night.
Golf worth playing:
Royal Canberra - bit of a dumb blonde, you'd not want to miss the best in Syd or Melb to play it instead, but if it will be in addition, why not?!
Melbourne (and surrounds)
I have actually not been to Melbourne (8hrs south of Sydney by car, or an hour by plane), but is is well known as a cultural and shopping hub with a great cafe and small bar culture, world class restaurants. It has been described to me as a really European city. It is also Golf HQ for Australia. Mornington Peninsula is nearby and doable as an overnight trip. The Great Ocean Road is another excursion you can do from melbourne, allowing a few days.
I'd invite any of our Melbourne-based posters to dispell any bullshit in that, add their own thoughts etc.
Golf worth playing:
Royal Melbourne (West - MacKenzie/Alec Russell, East - Russell)
Kingston Heath (Dan Soutar, bunkering by MacKenzie)
National Moonah (Norman - on Mornington)
National Old (RTJ Jr - on Mornington)
St Andrews Beach (Doak - on Mornington)
Other Sandbelt courses such as Victoria, Metropolitan, Commonwealth, Woodlands, Peninsula and Yarra Yarra are also highly rated.
Tasmania (for the Boomerang)
There is bugger all for your missus and child(ren) to do around the vicinity of Bridport where Barnbougle Dunes and The Lost Farm are located. Unless they play golf, in which case they are very welcome to play with us.
Golf worth playing:
We're playing The Lost Farm (Coore) and Barnbougle Dunes (Doak/Clayton) and they are the only courses worth playing down there.
For non-golfers while we are at the Boomerang
I would suggest that's a good chance for non-golfing spouses and children to either spend some time seeing Sydney (1hr flight north of Bridport), Melbourne (a short hop of a flight Melb > launceston or a ferry ride (a few hours) from Melbourne).
Or if there will be kids in tow or they could spend the three days on the Gold Coast in Queensland (90mins flight from Melbourne, an hour from Sydney) going to the theme parks (Warner Bros MovieWorld, Dreamworld, SeaWorld, Wet and Wild Water Park) etc.
There are heaps of other ideas of stuff they could do. That's just a couple.
The outback
You can fly into Alice Springs for a taste of the outback and can easily get to Uluru (Ayers Rock) from there. About 2hrs flight from anywhere on the east coast).
While not world class, Alice Springs GC does get some love in Aus.
Great Barrier Reef
Up in North Queensland choose from Hamilton Island, Airlie Beach, Lindeman Island, Hayman Island etc to see the reef. Hamilton Island has an airport and you can do daytrips to Hardy Reef by boat or sea plane to see the reef, do some snorkeling, go on the glass bottom boat to see the coral etc. I highly recommend it if you can spare the time.
Western Australia and South Australia
A fair way west (though Adelaide, capital of SA, is nearish to Melbourne) and if you are on a restricted itinerary, perhaps too time consuming to include. I cannot vouch for either, but have heard good things about both.
New Zealand
The South Island has the best scenery, but the North Island (where Auckland is, if you're flying Air New Zealand from the West Coast of the US and have a stopover there) has the best golf. If doing a one-way car hire between arriving from the US and going to SAus or vice versa, you could buy US > Auckland air tickets and do the NZ > Aus legs with a local carrier.
Though it is quite small, so driving around can be done and there is a car ferry from Picton at the top of the South Island to Wellington at the bottom of the North Island which takes 90 mins and takes you through Marlborough Sound which is really scenic. New Zealand has scenery the equal of anything I have seen in the world.
If doing NZ before Aus, you could go US > Auckland > drive south to Christchurch > Syd/Melb. If doing NZ after Aus, you could go Syd/Melb > Christchurch > drive north to Auckland > fly home.
Golf worth playing:
Paraparaumu Beach (a links near Wellington, the drive to the course is via a pretty coastline)
Cape Kidnappers (Doak's course, near Hawke's Bay on the east coast of the North Island)
Titirangi (a MacKenzie course in Auckland)
Kauri Cliffs (clifftop course, up north of Auckland)
South Island I am no help, sorry.
Travel tools
* For flights within Australia the best airlines are Jetstar and Virgin Blue.
* GoogleMaps overestimates driving times quite a bit.
* All golf clubs listed in Aus are accessible with a friendly phone call or letter and a relatively healthy wallet. Expect to pay from AU$100 for some Sandbelt bargains to $170 or so for NSWGC to $395 for Royal Melbourne without an introduction.
* Easycar has ben good to me with rental cars and I see they now service Australia. Worth looking into.
* If you don't want a car at the Boomerang, Barnbougle Dunes does airport transfers, but they are slightly pricey.