I hear ya man. I never did anything under 80mph driving out in the prairies (Alberta to Manitoba). The best I did was Medicine Hat to Moose Jaw in 2:45. The same goes for the whole trip back to Ontario through the states, 80mph was not only a minimum speed (towing with the taller 5th gear doesn't do much for keeping oil pressure up...) but it seemed to be the social norm.
The bottom line is, flow of traffic is your best bet, unless they're being a total ass about it.

I'll never forget a speeding ticket I got going through MT. Was doing 95 in a 70, and thought we were going to get wrecked my the officer when we saw the lights on. Ticket was $20 paid on the spot, or come back to MT and fight it. lol. Kept the ticket.

In a perfect world, I think a posted limit of 120 is acceptable on 400 series highways outside of major city centers. 100 through the GTA, because lets call a spade a spade here... not many people can do that speed acceptably. That could cause some kind of traffic issues with the increased volume and reduced speed, but meh.. we're just talking here.

As for waze, if you aren't using it, you should be. Google gets it's accident information from waze users. The app is incredible in terms of displaying current conditions.
I wish the navigation was a little more user friendly, in terms of selecting a certain location on a map vs from a list.
Either way, Royalty Wazer here; Rank 7000, 116,164pts