Depending on how much you like to climb, this will probably factor into your route through BC. The Trans-Canada(#1) east of Hope is probably the most tame. You basically have three passes (Jackass in the Fraser Canyon, Roger's between Revestoke and Golden, and Kicking Horse between Field and the border).
For the most part, BC has excellent shoulders though there are small stretches that don't have much. Kicking Horse Canyon immediately east of Golden comes to mind. At times when there is no shoulder, there may be a passing lane.
The Crow's Nest (#3) west of Hope is probably the most aggressive route across BC with the most climbs. I highly recommend this route. It is extremely beautiful. But be warned it is hilly.
The Coquihalla (#5) from Hope has two, long sustained climbs. There are in the vicinity of ~7% for 15 to 20 km each.
Check out this
site. Lots of information on BC roads.
As for the #17 around Lake Superior, I found it to be in the top three for scenery when I cycled across. I have motorcycled the southern shore years previous, but I really don't think that it has the scenery that the northern route does.
Traffic can be bad at times, but if you get early starts in the morning, it may help alleviate some of the RV traffic.
I found the dodgiest road, the stretch from Ste. St. Marie to Espanola (and probably on to Sudbury if you continued that way). I also met cyclists that have actually bussed, or considered bussing that stretch.
Heading south at Espanola through Manitoulin Island, then ferrying over to Tobermory would be longer than cutting straight across from Sudbury - but it would be quieter and more scenic IMO.
Anyway, I'm sure that there will be more people chiming in from various parts of the country.