TL;DR?
I once got 5M frequent flyer miles for ~$10K.
Please, somebody, anybody, remind me how I did this.
I really can't think how that would have been possible. No single transcon roundtrip would have earned
100,000 miles. Are you sure your numbers are right?
That said, definitely enjoyed the US Airways days. Used to remark on how easy it was to get upgraded (followed with the proviso "of course, nothing happens when you get up there, but you get up there!")... plastic cups of quite poor wine even on long flights in F, but decent food, great FAs, and some comfy seats.