Just wondering -- did you consider Southwest (WN)?
I see they have 2 non-stops daily DEN-PDX and couple more 1 stops.
Never a change fee (although you might have to upgrade from a Wanna-Get-Away fare to a full fare). You don't have to tell them why you need a change (death in the family), just change it without a fee anytime!
Not to say that Alaska isn't nice too.