Thanks to both of you. I guess I'm looking for advice now.

I see two options:

#1) re-book the originating flight. This sucks because I have to get to the Kelowna airport at 4am with a wife and kid. NOT a positive thing! It also sucks because I would have 6 hours at YVR instead of 1.
#2) chance it. The next flight to Houston, however, would mean 7 hours in YVR plus not arriving in Houston until after midnight. The flight after that means 12 hours in YVR and a redeye.

Choosing #1 means 100% chance of having those negatives while #2 mean X% chance of having those negatives (but, obviously, some chance of having it work out nicely). I suppose I'd like to narrow down the value of X. Are we likely to make it?

What would you do?

No, we don't have Nexus, etc.