A few points:

- starting outside of your home city/country - because a RTW ticket ends as soon as you arrive at your starting airport, it is advisable in some circumstances, to starts elsewhere than your home airport - this allows you to do some part of the trip at either end of a RTW. E.g. is living in SFO, you could start it in LAX and do LAX-JFK-DFW-SFO......live at home for 11 months or so......SFO-LHR-DEL-HKG-SFO (and this is the simplest to achieve your outlined objectives KSinNYC - you could add other sectors withint he routing above if on a xONEx).

- starting outside of your home country, in addition to the above, allows you to buy the same ticket for a cheaper fare. E.g. I live in LAX, but I purchased my DONE4 in BKK and started it there....travelled to HKG and then Aust and now back in LAX... will do a couple of NA trips on the ticket (LAX-SJD, LAX-DFW-ORF-DFW-LAX) and then continue next year LAX-LHR.....BKK.

- the additional benefit of starting outside of NA, is that the xONEx restricts you to 4 segments and 2 stopovers in your continent of origin. So if you started in LAX or SFO you could only do LAX-JFK-DFW-SFO, whereas if you started outside of NA, you could not fly into SFO from another continent, and within NA do for eg SFO-JFK-DFW-SFO-ORD-SFO...and then continue on to Europe and DEL.

- the main issue of starting outside of your home country/city is you need to get to that starting point. Eg. you would need to go SFO-LAX on a separate ticket, and also return from LAX-SFO at the end of your RTW (if you do not choose to buy another one to start from LAX). This can be done using $ or miles - obviously cheaper to fly SFO-LAX than SFO-BKK. But the DONEx fares (for example) are considerably cheaper ex-BKK than ex-NA.

Hope the above explains it a little more. Feel free to ask further questions and I am sure others can chime in.