OK, I think I have my final itinerary locked in, after spending 2 days choosing between St Lucia or Barbados:

JNB-HKG-DEL-NRT-PEK//PVG-HKG-JFK-UVF-MIA-MEX-YVR-DFW-LAX-BRU//CAI-MAD-HEL-BUD-xLHR-DAR

I will be calling Dallas RTW AA desk tonight to book this (have to wait until Midnight from Melbourne). Soon I can finally stop learning airport codes and plotting flight paths and start researching accomodation and activities, woot!

24 year high for the Aussie dollar yesterday fits in nicely with my planning hey! South African Rand also just dropped a bit, making my DONE4 $150 cheaper than last week.

Last 3 questions:

• If I leave flights as OPEN, how/when do I pay taxes, at check in? Is it better just to pay it all up front or do I risk some taxes not being listed on the paper ticket and chasing refunds?
  
• How soon before a booked flight can I change it?
  
  I'm trying to find the best way to Cancun, either fly MIA-CUN, maybe find a budget mexican carrier to take me MEX-CUN, or I can get to Austin and fly Viva Aerobus to CUN, but perfect thing would be some sort of cruise from MIA-CUN that's affordable. I want to do a G.A.P Adventures or Intrepid 15 day tour overland from Cancun to Mexico City and continue on my DONE4.
  
  I could go overland from Shanghai to Hong Kong, seeming I'm already going from Beijing to Shanghai that way, and instead use that extra sector for the non-OWE flight from MIA-CUN..... I can't decide. I could also spend a few days in Seoul or Taipei, what to do, what to do?
  
  
• If I book MIA-MEX, but then I end up making my own way from MIA to MEX, can I just keep going without paying a rebooking fee?