First off - thanks to everyone for your input - very much appreciated.

I started thinking of this as a way to do the primary trip low cost and throw in likely North America (Omaha) trip along the way.

Now I'm thinking more in terms of going DONE4, and optimizing for going on some interesting vacations in business class in addition to the upcoming Botswana trip.

Here is what I'm thinking (basically adding a trip to Costa Rica and later Canary Islands).

1: JNB-SYD: intercontinental
2: SYD-CNS: 1st of 4 (Southwest Pacific)
3: CNS-SYD: 2nd of 4 (Southwest Pacific)
4: SYD-SFO: 1st of 1 (intercontinental entry to North America without immediate transit & departure)
5: SFO-SEA: surface
6: SEA-DFW: 1st of 6 (North America)
7: DFW-SJO: 2nd of 6 (North America)
8: SJO-DFW: 3rd of 6 (North America)
9: DFW-SEA: 4th of 6 (North America)
10: SEA-LHR: intercontinental
11: LHR-LGW: surface
12: LGW-ACE: 1st of 4 (Europe)
13: ACE-LGW: 2nd of 4 (Europe)
14: LGW-LHR: surface
15: LHR-JNB: intercontinental

Possible add-ons would be 1 round-trip in North America and 1 round-trip in Europe.

So - feedback on this proposed itinerary?

Any suggestions on how to actually go about booking the ex-JNB ticket? I've read about contacting local AA office to create the trip and transfering to country of departure. Any other advice?

Thanks all.