Thanks so much for all the help out there - I know you will roll your eyes at my next few questions but here goes:
Due to an unavoidable work commitment we have had to postpone our trip to the latter half of next year (and must fit in with paragliding weather in turkey for my better half which is apparently August/September) thus my first question is how far ahead can one book a DONE4? Obviously, using the Oneworld Planner is a guessing game as far as dates go if my trip finishes more than a year from now. Am I being completely ridiculous setting up the framework of this trip so far ahead?

Next, due to starting so late in the year, I have had to reverse our itinerary. I have (thanks pandaperth for suggesting I better utilise the number of sectors) come up with the following itinerary:
AMM-IST-KUL-SYD-HBA-SYD-LAX-SFO,SLC-DFW-MEM-ORD-JFK-LHR-FCO-AMM
I tried originating in Cairo however, the planner quoted me an increased US$8,000?? We intend to do Turkey & Greece in August 2014, head home for Christmas, quick trip to Hobart in February (thanks pandaperth) and then recommence the American and Italian content in May 2015.

I would have liked a stop in Paris however, I think I can only have 2 stopovers more than 24 hrs in the origin country - thus IST & FCO are the two best ones for us. Am I correct or is the bug that plagues itineraries starting with an FJ flight responsible?

I ran this itinerary through Mileage Monkey and came up with 28,247 miles - would I be better switching to the AA program and forego QF? Icag08 advised me to look into the AA Platinum Challenge, however, even after reading up on this forum and elsewhere I'm still not sure if it will benefit me in this situation as I think we have to fly 25,000 miles before we qualify? So as we are only flying 28,000 in this trip, is it worth it? Of course, it could be me incorrectly deciphering code with which I am totally unfamiliar.

Thanks again for those of you brave enough to wade through my ponderous list of problems, undoubtedly caused by my own ignorance!