Start by asking the provincial governments.
Here are two starting points:
The Province of British Columbia - Discover BC
Government of Alberta: Tourism
I do not say these are the best starting points, but they seem to be authentic government services, and not merchants pretending to be official sources of information, but really interested in routing your money into their pockets.
July in Alberta has one highlight that you really must experience, the Calgary Stampede. This happens early in July, and is the loudest and most boisterous event in Alberta every year. The whole city participates; for example, you can step out of your hotel room and be greeted by Calgarians cooking a free pancake breakfast for you.
British Columbia is a terrific place to visit, full of wonderful places to ride and great scenery to view and photograph. The coast road north from Vancouver is called Sea-to-Sky, and is a treat to ride. It keeps going as far north and as far into the interior as you want to go. I think it goes over the pole and into Russia. :yesnod:
From the above starting points, you can request maps, brochures, and information packages from government sources and from all kind of tourist attractions: dude ranches, fishing outfitters and guides, hotels, zip-line sites, boat rentals, glacier hiking sites, and on and on. Your mailbox will be as full as you want it to get.
I crossed into Canada at Osoyoos BC in 2006, and the first question I was asked was why I had chosen such an out-of-the-way crossing point. It occurred to me to reply, "Well, I figgered that you rubes wouldn't know marijuana from oregano." but I merely said that I was riding a scenic route, and what more appropriate place to cross than this lovely town.
Meanwhile, I like your choice of US-93 to go north. This highway follows the Salmon river downstream (= northward) through a generally narrow valley. The river is too turbulent for navigation (so said Lewis and Clark) but that makes it scenic and lovely. You are almost compelled to ride I-90 west to Spokane en route to Osoyoos, but the route from Spokane WA to Osoyoos goes through very scenic country and past the Grande Coulee Dam, which is worth a long look.
You will enjoy your ride immensely, as I did. I did no planning; I just rode out of Toronto ON headed west to Vancouver, and I knew I would find loveliness wherever I rode. If you give the provincial governments a chance, they will give you a wealth of information. Most of it will be true.
Good luck on your venture.
Keith