Thanks for the replies and the advice. lucky9876coins, I enjoyed reading your travel journals during my lurking period!

I do accept that not all fares will go everwhere or route to where I want them (unfortunately!) but is there any way, given a specific fare, to find out exactly the cities to which that fare applies. I checked the "fare facts" page that I link to above and even the "fare rules" linked from the itinerary page. The rules just list a broad range of flight numbers which do in fact include the flights I was checking to/from ORD. In fact I did seem to meet all of the requirements. But where is the rest of the information that dictates the allowed cities for that fare?

Routing through PHL on US is interesting, mahasamatman. I'll have to play with that a little. I do have a trip to New York coming up directly before that which I could work in there too (with a possible stopover in PHL if I need), but I need that for the third of my fly3 trips, so that I can get a new 5,000 RDM for the China trip.