I am planning a trip for September, 2010. I want to fly into Kalispell, Montana and do a one way driving tour from Kalispell through Glacier National Park into the Canadian Rockies, flying back from Calgary.

This seems like such a "natural" trip that I was amazed that upon checking rental car companies at Kalispell, only one allows such a one way drop rental to Calgary.

My fear: what if that company adopts such a policy between now and my trip?

Has anyone done a trip similar to this, and if so, how?

Haven't done that trip but another thing to keep in mind, depending on what time in September you arrive, the Going to the Sun road could be closed due to weather or construction. To my knowledge, ground transportation from Kalispell into Canada is impossible except for private auto.

How much time do you have to travel? We were also going to do this trip but taking cars across the border was a problem--so we just did the Canadian Rockies. If you are a hiker, you could spend 2 weeks in the Canadian Rockies, visiting just Banff, Lake Louise and Jasper. It is one of my favorite places to visit. I have a couple of trip reports on the Canada forum.