Hmmm, Windermere is I guess about 3.5 hours
Sort of thought BC was too far for the "3 hour window", but you're right, it isn't really.
Problem is, checking out the BC parks availability for the long weekend ... and it looks pretty grim. discovercamping.ca is the website to check. I'm not sure about Alberta parks, but in BC the reservable sites are reservable up to 3 months prior. I've never really tried reserving a spot in Alberta (I always camp in BC anyhow
) so I don't really know how it works over here.