I've done it twice from Toronto - once in '87 on my 900f, and once in '89 via Alaska with the 900f and a Velorex sidecar.
Best advice I can give is to allow yourself more time than you think you'll need. If you're doing it at the height of summer, plan on lots of RV's/slow traffic through the Rockies (and watch out for deer/moose/bears!). As well, are you planning on stopping and seeing the sights at all, or are you just going to blast your way from TO to Van with your head down? So many things to stop and see in that vast space, so you might want to also build in extra time for being a tourist.
Be sure to bring tools besides your little bike tool kit (and extra oil, chain lube etc), as well as good rain gear and warm clothing. As well, taking out an AMA membership with MOTOW (the motorcycle equivalent to AAA/CAA) would definitely be a plus, as when you're stuck on the side of the road at Rogers Pass, nice to know that you have a couple of options (and hopefully cell phone service!).
Invest in some good waterproof bike luggage - tank bag, passenger seat bag, saddle bags. And when you get the luggage, load your bike up with all of it (and the luggage is packed with stuff), and do a 'dry run' on your bike (like maybe up to Collingwood?). How does the bike feel with all that stuff? How do you feel on the bike, particularly since you'll have more limited movement on the bike? BTW have you ever done a long ride like this before? Glad to know that you're thinking of doing this trip on a bigger bike than your Honda Dream!
As far as a route goes, just getting out of Ontario probably takes the longest! However, the north shore of Lake Superior is beautiful, so you may want to spend a bit of time just exploring that area. Here again, it depends on how much time you want to devote to this trip. If you want to ride, say, 500 miles a day (and figure 10+ hours to do that), then that's 12 days of just riding and not seeing much else (6 days out, 6 days back). If you really wanted to take your time and really make a 'vacation' out of it, I'd think that 3 weeks would be a very comfortable amount of time -- that way you can ride at a more relaxed pace, maybe spend a couple of days in one spot, and if anything does happen to go wrong on the road, at least you have that time cushion built in to your vacation.
When I did Alaska in '89, it was a 31 day trip. First day out, I blew a piston 150 miles east of Thunder Bay. Had to limp on 3 cylinders from Pic, Ontario to Thunder Bay, and spent a week there while the Honda shop was waiting on a Wiseco piston (don't forget, this is pre-internet/cell phones etc!). So then I had to really make up time -- did Thunder Bay to Saskatoon in one shot (1100 miles in 21 hours), then to Edmonton from there, and then was back on track to catch a ferry out of Skagway, Alaska several days later (I had a reservation on the ferry, so I had to be in Skagway by a specific date). Hadn't planned on the engine troubles, so thankfully I had that extra time, but I had to ride like an Iron Butt veteran for a couple of days to make up for the lost time....not fun.
The one thing I did not do on either one of these trips was to camp along the way, and I'm glad I didn't. More crap to have to carry on your bike, and besides, after being in the saddle for 10-12-14 hours, did I really want to have to set up a tent at a campsite in the dark in the rain, then have to leave my stuff, climb back on the bike and find some place to eat, then the next morning have to pack all this wet camping stuff back on the bike? Uh, no thanks.
As far as going through the states being nicer/faster, I've been across the country through both the states and Canada, and one is no nicer nor necessarily quicker than the other. Can't see how you can beat the Rockies in BC, and the north shore of Lake Superior is (IMO) far more attractive than riding through Detroit/Gary/Chicago. But here again, if the speed at which you complete this is your aim, then maybe you need to ask yourself the purpose of this trip -- is it for personal accomplishment, or is it a vacation?
No matter which it is for you, plan for more time than you need, definitely more money than you'll need, expect the unexpected (both good and bad!), and try to have some fun.
