Connection in NRT from AA to CX
 

I intend to break my AONE4 trip by buying a separate return ticket Tokyo-USA on AA. The inbound routing to the USA is set, however the return to Tokyo is not. From Tokyo I would go to Singapore with little delay as that is the intended destination for the Asian phase of my RTW. I also plan to overnight at the USA gateway before beginning the trans-pacific flight, which I hope to upgrade to business class from coach.

Option 1
WAS-DFW-NRT-HKG-SIN
Pro’s – earlier of 2 flights DFW-NRT arrives with ample time to connect to either CX flight to Hong Kong, both of which have first class.
Con’s – poorer selection of lounges, very late arrival into HKG, very long trans-pacific sector

Option 2
WAS-LAX-NRT-HKG-SIN
Pro’s – BA lounge at WAS, flagship lounge at LAX, shortest trans-pacific sector
Con’s – Short connection (1:20) at NRT to last CX flight to HKG, may need overnight at NRT instead of HKG making for a long travel day NRT-HKG-SIN (all regional business class)

To me, the biggest uncertainity is the short connection time for option 2. The LAX flight is the last to arrive at NRT which means it may have to wait for a gate to unload. Not what I would want to happen. If there is a check-in desk for connections without the need to clear customs and immigration, that would mitigate some of my concerns. For those who travel thru NRT often, which would you select, #1 or #2?

Thanks….

N.B. There are 2 tickets involved, a return NRT-WAS and my AONE each with its own PNR.

I'd go for option 2. I don't think gate congestion at NRT is a problem - I've never seen any. And the transit time is very short - I have done same plane turnrounds with no problem. International transit simply involves going through a security check at which you need to show an onward ticket (or BP). Then there is a CX transit desk near the gates which will issue you the new BP. To be safe just try to make sure you are as near first off the plane as possible to get to security first, but I have never had to wait more than 10 mins or so there.

I would do option one. I have backtracked before by going LAX to DFW to NRT (extra mileage). It's not as bad as you think. The DFW flight gets into NRT a bit earlier than the LAX flight. I believe once you get into NRT, you have two CX flights to choose from; 16:20 and 18:30. There's also an earlier one, but I believe it stops in Taipei.
As far as lounge access is concerned, the lounges in the States are nothing to write home about. It's the one HKG where you should spend more time in.

I'd go for option 1.

On a practical level, if you want to upgrade the U.S. -> NRT leg and you're targetting a specific day, I would think the routing would depend more on upgrade availability more than anything else. In my experience, ORD is very hard, DFW can be difficult, LAX or SJC are often easier (and not sure about JFK - haven't looked at it in a while).

time change in my favor
 

I chose option #2 via LAX. The change to summer time in the USA and the fact that Japan does not means that the LAX flight arrives 1 hour earlier in April. With 2:20, that should be ample time. And I already have confirmed upgrades on the WAS-LAX-NRT sectors.