It's crappy in YOW - no MLL in transborder. Not many choices for food/drinks either.
I have never connected through YOW, but I'm pretty sure you can't get in domestic without a boarding pass. Plus, you probabaly have to clear through Canadian customs and pre-clear US customs.
On the brighter side, there is free Internet throughout the airport. Perhaps you can kill a few hours with that.
Have a good flight!