Sydney to New Orleans in F.

Sydney to New Orleans in F. which route, which airline ( I want QF status credits), prefer A380 but which lounge is best Dallas or LA

Well the choice is fairly easy. 

The only nonstop flights between LAX and MSY (new orleans) are on Southwest, Delta, and United, none of whom are partners with Qantas.   Unless you want to have an additional stop, which would be in Dallas anyway, it makes the most sense to fly straight to Dallas. 

Agree with RealKid - its a no-brainer to fly into Dallas on Qantas then take the cheapest/most convenient option down to New Orleans

Although if you have the time, the stopover via LAX and DFW might mean more points and SC. 

QF SYD-LAX in F gives you 90 SCs.  SYD-DFW also gives 90 SCs.  If SCs are your priority, then go SYD-LAX, then AA LAX-MSY (via DFW) in F and you'll then earn another 40 SCs.

Not sure where you got the 90 SC's for SYD-LAX Phil, it's 270 each way according to the Qantas website in First.

Oops.  You're correct.  It's 270 SCs for both SYD-LAX or SYD-DFW in F.  Then it's another 40 SCs on AA LAX-DFW in F.  It's 90 in Y.

And if flying AA LAX-DFW in F you'll get access to AA's Admirals Club lounge at LAX Terminal 4.  It's a very good lounge, several steps above AA's standard lounges, with very acceptable food & drinks, wi-fi, showers, comfy seating etc. 

I'll leave it to others to comment on lounges at DFW.

And while you're in New Orleans and if you like genuine trad jazz, be sure to go to Preservation Hall.

Phil,

The Flagship Lounge may be used at LAX Terminal 4, which is considerably better than the Admirals Club as per the oneworld lounge access rules below:

oneworld lounge access for First Class or Business Class customers

Indulge yourself before departure in a wider range of airport lounges when you fly First Class or Business Class with anyoneworld member airline.

• Customers flying First or Business Class have access to the equivalent class of lounge regardless of their frequent flyer status. First Class passengers may use a Business Class or frequent flyer lounge if a First Class lounge is not available.
• First Class passengers may invite one guest to join them in the lounge. The guest must also be travelling on a flight operated and marketed by a oneworld airline.
• Connecting between oneworld marketed and operated flights:
  • First and Business Class customers connecting on the same day of travel, or before 6am the following day, can access the lounge when travelling between an international long haul (a oneworld international long haul flight is defined as an international flight marketed and operated by any oneworld carrier with a scheduled flight time longer than 5 hours) and an international short haul or domestic flight (and vice-versa).     
  • Lounge access will be determined on the international long haul ticketed flight (either First of Business Class) regardless of the ticketed class of travel on the international short haul or domestic flight.
  • You must be prepared to show your boarding pass or itinerary showing travel in First or Business class on the international long haul flight, in order to access the lounge before your international short haul or domestic flightc

You're correct TRB.  I got confused over AA's lounge naming system.

In addition to everything else mentioned, flying via LAX means a few more hours spent in AA domestic F instead of QF international F. If you're gonna buy an F ticket you might as well get your money's worth.