So it became cheaper to fly to Denver on Alaska Air ($150 change fee for the two of us), then Denver to Orlando on US Airways, due to the credits. So the plan was to fly to Denver overnight the 3rd/4th, stay in a hostel for a couple of nights, and then fly to Orlando. Except when we tried to actually book the US Airways flight, the credit went poof. No unflown credit at all. Apparently the original booking was for May something of last year, except that in actuality a brand new set of tickets was issued last July, supposedly resetting the clock.
Well, being stuck for a way home, I called US Airways back and explained the situation again. We're in Anchorage and our only way home is using the credit that you assured me we had. If we had been advised differently when we spoke to you the past 20 times, we would have planned differently. Eventually I got a sympathetic agent who informed me that if it was an "emergency," then the credit would be honored. But it couldn't possibly be an emergency if I wasn't trying to fly the same day. Net result: a one-time offer to use the credit overnight on July 4/5.
So we took it, for the low, low price of only another $300 out of pocket change fee plus $15 per bag check fee. $330 later, we had the unmitigated pleasure of spending the 18 hours between the overnight Alaska Air flight and the overnight US Airways flight sitting in the Denver airport. We're now in Philadelphia and the plane to Orlando is delayed. Ugh, I hate airports!!
On a happier note, Alaska was fantastic!! I'll post details once I've eaten and slept.