From the Vancouver airport, if it were me, I would make my way down to White Rock (and the International Peace Arch), and then east along 16th Ave to 264 St. From there I'd go south to 0 Ave, right along the border, and follow that to Hwy 11 right below Abbotsford. From there, get a good map of the area -- the Abbotsford travel agency has some -- and follow Vye Rd. and onto Old Yale Rd. and up Powerhouse Road, Wells Line Road, Interprovincial Highway, Boundary Rd. etc. ... it kind of follows the contours of the mountains through there ... VERY scenic. You'll be in Chilliwack, and I'd go through Chilliwack on Vedder Rd, onto Yale Road (crossing the TransCanada).
You might have to ride the TransCanda for a little while between Yale Rd and Agassiz Rosedale Hwy, but once you get onto Agassiz Rosedale Hwy you can get up to Hwy 7, which will take you to Hope.
From Hope, you've got three choices (Hwy 1, Hwy 3, and Hwy 5). I think Hwy 5 is the Coquihalla and I don't believe you are allowed on that one, but I might be mistaken. However, either of the other two choices are probably OK. Hwy 3 is likely the most quiet of the bunch. One thing to note here ... whatever direction you choose to go in BC from here on will not have shoulders and will be very rugged and fairly remote ... unless it is the middle of July, in which case the roads will be clogged with RVs.
If you want to end up in Banff
relatively quickly, I'd go with Hwy 1, but be aware that the traffic can get a bit annoying. If you've got lots of time, I think I'd meander along on Hwy 3 and some others there along the south of the province, or I might make my way north from Kamloops up Hwy 5 (you can cycle it from this point - I have, it's quite nice) to Jasper
If you do the south route, I'd come north on Hwy 93 to Radium Hotsprings (lovely area!) to Banff. If you're in Jasper, I might ride the Icefield Parkway south to Banff. From Banff, take either Hwy 1 (TransCanada) or the 1A. The 1A is more scenic and has very light traffic, but the road is pretty rough. The TransCanada is busier but there are wide shoulders so it isn't too bad. I'd stay on one or the other to Calgary.
Again, if it were me, from Calgary, I'd make my way to Drumheller (to see the badlands!) Drumheller http://www.tyrrellmuseum.com/
is interesting. Then I'd take Hwy 9 out of the province into Saskatchewan (but I would avoid Hwy 9 prior to Drumheller). However, if you wanted something a bit more scenic, and if you've got time, I would make my way a bit further north and cross into Saskatchewan at Lloydminster, although Hwy 16 can be pretty busy too.
If seeing Banff and Calgary isn't that important to you, I'd head south from Jasper to Saskatchewan River Crossing and then east on Hwy 11 to Red Deer and across to Drumheller from there. Hwy 11 is the most beautiful highway I've ever ridden.
Saskatchewan ... hmmmmm ... well, you might first try to pick up a good map that will tell you which roads are paved, because from here to Ontario not many of them are. Qu'appelle Valley on the east side of Regina is nice ... but Regina isn't particularly. I think if I were you, I'd aim to enter Manitoba around Russell, just south of Riding Mountain National Park ... and I'd take a little trip into Riding Mountain National Park http://www.pc.gc.ca/pn-np/mb/riding/index_e.asp
... you'll be desperate for some scenery by then!! Oh, but a warning ... avoid Yorkton at all costs ... it is the Bermuda Triangle of the prairies!!
There are several routes you could take through Manitoba ... the quickest would be Neepawa, Gladstone, Portage La Prairie and then Hwy 26 into Winnipeg (NOT the TransCanada, unless you've got a death wish). But if you've got time, head south from Neepawa to Spruce Woods area http://www.gov.mb.ca/conservation/pa.../spruce_woods/
- there's a nice campground there, and a desert which they'll take you out on with a horse and cart ... it's interesting. Then I'd probably go over to Hwy 34, down to Hwy 3 to Morden (good breakfasts in the hotel there!), and north on Hwy 3 to Carmen (lovely swimming facilities and park) and into Winnipeg.
Note: I would strongly recommend avoiding the TransCanada across Manitoba as much as possible. There are no shoulders ... you're just out there with all the traffic. Other cyclists have died trying to ride the TransCanada through Manitoba, and there are much better choices for roads - either Hwy 2 or 3 will get you across to Winnipeg with a lot less hassle than the TransCanada.
From Winnipeg, I'd go up to Bird's Hill Park in the north (you might camp there, it's nice), and then out toward Elma on Hwy 15. Then get onto Hwy 44 to West Hawk Lake http://www.gov.mb.ca/conservation/pa...ell/index.html
... but try to avoid that road on a weekend. There are no shoulders in Manitoba, and that road will have a lot of RV traffic on it on the weekends. There is some nice camping in the West Hawk Lake area.
Then you have to get onto Hwy 1 (or Hwy 17 as they call it in Ontario) but it isn't too bad for traffic, and it is scenic. Kenora's kind of nice - lots of lakes around there. I've only been out as far as Dryden, so I don't know if you'd want to head south and take Hwy 11 out to Thunder Bay, or just stay on 17.
I have heard that Hwy 17 north of Lake Superior is not a good road for cyclists, and I've heard that most cyclists prefer to drop into the US and go under the lake ... but someone else will have to confirm that for me.
So ... that's a brief tour of western Canada!!
You might be able to get some more info from here: