Well -

It took me a while, but I found Linacre. Combined with Osoyoos, I guess you'll be taking the Crowsnest or - if you have a mountain bike - the Kettle Valley? If you want to get a little extra of the Rockies, you can take the Elk Valley forest road (unpaved after Elkford) up from Sparwood, spend some time at Elk Lakes Prov Park - superb and remote - then cross over to Kananaskis on the Telephone Rd (unpaved).
From there you could take Highwood Pass Road to Longview and out onto the Prairies.
Crowsnest is OK, but you don't get much of the Rockies.

I biked western Sask a number of years back. Grasslands Natl Park is quite nice - esp early in the summer before it dries up. The roads south of the TransCanada are quite lovely and have very little traffic - but the towns, as you probably know, are also drying up.