This brings back memories of last year... I was in much of a similar situation.
I had to be in Edmonton for Wednesday-Friday event AND be in a wedding party on Saturday at noon (near Ottawa). It was absolutely impossible to get the AC overnight on Aeroplan, so I ended up flying Edmonton-Calgary-Hamilton-Ottawa on WestJet, which saved me roughly $1000!! Bottom line: I left Edmonton around 9pm, arrived at YOW just after 9am and was in good shape for the noon wedding (which was a further 1.5 hour drive from YOW).
Moral of the story: try to (1) book well ahead, or (2) take lots of caffeine pills.

If you are making a US connection, I guess your only option is AC, but you can also call Aeroplan and they might route you through the US.