I'm trying to firm up a route. I understand surface segments are now included, but using open-date segments may be used by specifying LON rather than wasting a segment on LHR-LGW. (I may be wrong on this though.)

Anyway, I've put this route to my TA:

wlg-syd-jfk-mia-sfo-dfw-sea-dfw-lax-lon-krk-lon-nrt-hkg-nrt-syd-wlg

The TA comes back with 2 problems:

1. I've 2 too many segments as LAX flies into LHR and KRK goes from LGW. Can I put LON if I say LAX-LON-KRK-LON are open-dated?
2. Can I have SYD appearing twice? I only want one stopover from that, the other is a transit.

Mileage Monkey is OK with it...?

Thanks.

1. This might be pushing it a bit. I've only ever done this sort of thing where there were multiple alternatives (e.g. LON-WAS-NYC).

2. No problem with SYD twice that I can see. You could even stop there both times if you want since you have no other stopovers in SWP.

If you had to, you can simplify the last few segments of your itinerary:

...lon-nrt-hkg-akl instead of lon-nrt-hkg-nrt-syd-wlg

3 segments instead of 5; the 2 freed up can be used to solve your LGW-LHR surface sector problems

Using pandaperth's idea, you could also get a cheap return WLG-AKL and do something like:

akl-hkg-jfk-mia-sfo-lax-dfw-sea-lhr,lgw-krk-lgw,lhr-nrt-hkg-akl

where the first visit to HKG is a transit without stopover, and you have an additional sector left over to add in wherever is appropriate (or to finish with NRT-HKG-SYD-WLG I suppose). Another option might be to fly directly in and out of LGW; my first effort for this is:

akl-hkg-lax-sfo-dfw-mia-dfw-sea-jfk-lgw-krk-lgw-fco-nrt-hkg-akl

again with a sector to add in to taste. Note that MM says there is no JFK-LGW flight but the oneworld timetable says there is one daily. Also note that while JFK-LGW is not ideal for mileage-earning purposes compared to LAX-LHR, flying in and out of LGW gives you two extra sectors with which to make up this loss.

I thought someone mentioned here that you can't use City codes when there are multiple airports in the city?

If you CAN get around the rule that will be great especially a lot of interesting Europe cities depart from LGW and wasting a surface sector (LHR-LGW) just does not make sense.

Unfortunately, you can only transit Asia when travelling from SWP to Europe or v.v.
So you cannot transit through HKG on your way from AKL to JFK

Leumas' starting segments of WLG-SYD-JFK are fine. Perhaps Leumas is thinking of taking the AA platinum challenge? Flying those first two segments on AA codeshares will gain >10,000 EQP enough to satisfy the challenge, even on a LONEx.

Thanks for everyone's input so far...

I'll be crediting towards QFF. SYD-JFK is one of the longest (if not the longest) flight you can have on QF with one flight number.

I'd like to try the HKG-JFK (or vv) flight on CX, but you can't really do that if you want to start in the SWP...

Another question - I just want to double check that I can start and finish at different cities provided they're in the same country?

mmmmmmmmmmmmmmmm

SYD-JFK 9,950 miles according to Mileage Monkey
SYD-LHR 10,573
MEL-LHR 10,503

Can be done: outbound SYD-LHR... (you're allowed to do this and still stopover in Asia later)
then inbound ...JFK-HKG-other Asian stops-finish back in SWP
or v.v.

Yes. So in your case you can start at WLG and end at AKL

All the One World Explorer rules are here

No-one issues open-date e-tickets for OW RTWs it seems, so you would have a paper ticket. And the reservations can then be in as many different PNRs as you wish. The ticket doesn't need to be reissued - an open-dated paper coupon for, say, NYC-WAS is valid on any flight between JFK/LGA/EWR and IAD/BWI/DCA subject only to the Not Valid Before/After dates and you having a reservation in the appropriate class.

uuuuuuuuuuuu

Well all I can say is that I have done it and it works. No problems, no pushback from anyone. The case where I can recall all the specific details was an ex-TPE CX-issued DONE3 which had LHR-WAS-NYC-LAX. In the end I flew LHR-BWI, IAD-LGA, JFK-LAX simply checking in with open-dated paper coupons. The BA and AA staff had absoultely no issue at all with this.

For taxes, if I recall they simply price the most expensive possibility. I was fine with that as a price of getting the flexibility.