I haven't travelled on one of these yet but have been playing around with availability to get a feel for it so when I do want to book it won't be so much of a mystery. I realise there's a few ways people go about booking YUPs & KUPS however this is what I do:
1. Go to the
www.aa.com site then select "multi city trip" in blue writing underneath the round trip and one way options.
2. That will take you to a page "multi city flight search" & I enter my origin & final destination under flight 1 ie if I want to travel HNL/xLAX/LAS/xDFW/RDU/xMIA/BGI I simply enter from: HNL to: BGI & the date eg March 20.
3. The only other thing I change from the default preferences is Section 4 "what is your cabin preference" instead of "economy with restrictions" to "business class & higher with restrictions" per what Serfty said above.
4. I leave Section 6 "Country of Residence" as United States but I think you can select Australia if you want to pay in AUD then click red "GO" button.
5. The search results return 24 options of flights for the entire journey at USD784.00 one way plus taxes. In the "cabin" column flights that offer First Class are highlighted in yellow. If a 3 flight option you want to see the first two flights in First Class but the MIA/BGI only operates in Business Class.
6. You can of course go via more cities just go back to the original multi city availability page then enter your stopovers individually but it's important to not have any more than 24 hours at any intermediate point otherwise the system will want to charge you sector fares.
7. On another thread someone had the example going HNL to AUA so you would break it down as follows:
20 Mar From: HNL To: LAS (returns flight options HNL/xLAX/LAS)
21 Mar From: LAS to: RDU (returns flight options LAS/xDFW/RDU)
22 Mar From: RDU to: AUA (returns flight options RDU/xMIA/AUA)
I'm not sure whether you can squeeze more than 6 sectors in each way but would be interested to hear if anyone had.