QF is a distance based program, so it is better off used for shorter flight. Their problem is hefty fuel surcharges (YQ). However, if you use QF points on AA flights, no fuel surcharge. So in your case, I would recommend that you use QF points for transcontinental flights in USA. Or use it on flights where AA miles are not good, such as flights on Emirates or Jetstar.
As you don't mind flying in economy, I would suggest using AA miles for SYD to YVR on QF if you can find seats, as it will only cost you 37500 miles pp (75000 for 2), so you will still have 137000 AA miles left. QF will charge YQ for about $400 pp. (Forget about flying business, it will be like trying to find a needle in hay stack, especially if you need 2 seats.)
Then use your QFF for transcontinental flights across USA, it will cost about 18000 points pp (+$2.50 in tax). This will leave you 214K QFF points. Of course you have more than enough points to go to New Orleans if you want to.
Then the question is really where you want to stopover on the way back to SYD.
1. Stop over in Japan:
- Why not consider a bit of luxury and fly JAL for 50K/62.5K on Business/First respectively (plus $5.60 in tax)? You should be able to find spaces from JFK to NRT on JAL quite easily. Of course you can always fly economy for 37.5K miles.
- On the way back from Japan to SYD, you can use QFF points for Qantas, JAL or Jetstar. On QF flights, it should be about 70K/55K/35K each for business, premium economy and economy. However the YQ will be about $300. Since you have enough points, and Tokyo (Haneda) to Sydney business seats are wide open on QF, you might as well treat yourself with business class, as you will pay the same YQ anyway.
2. Stop over in Europe
- It's not easy to find award flight on premium cabins from US to Europe, and on BA flights, they will charge YQ. So you might have to look for economy class on AA flights for about 20k AA miles each. But you will run out of AA miles if you want to fly on QF business class for 60K miles each.
- So you might want to use QFF points for USA to Europe flights, it costs around 25-28k pp on economy (AA and BA flights respectively), or 50-55k pp on business, but you will need to pay expensive YQ even on AA flights (like $235USD pp, more with BA)
- Then leaving LHR, even though its nice to fly QF business class for only 60k miles each, you will need to pay APD (some sort of luxury tax for departure on premium cabin out of UK). That's usually about $200-300 pp.
So the bottom line is, unless you really want to go to Europe, stop over in Japan is the obvious choice.
But if you really want to go to Europe, consider flying the other way, that is, SYD-DXB-LHR on business, then you don't have to pay APD. The fly economy when you depart from LHR to USA, or depart from another country and transit in LHR, then you won't have to pay APD.