Originally Posted by
fumje
Do you want to stay on UA metal as far as possible? Do you prefer quickest routing? Other considerations?
+1.
For JNB, United will not get you there. The best you can do on United is PDX-EWR-CPT (seasonal) and then something else to JNB (although if you want an African vacation I'd guess you don't want to end in JNB). If you are willing to stick with *A, then either PDX-IAD-[ACC/DAK]-JNB or PDX-EWR+JFK-JNB will get you there, although the latter involves a cross-city ride. Your best bet however may be Delta, either through ATL or AMS - 1 stop either way.
For NRT, it's easier, just head to SFO (or LAX) on UA.