The Chateau Lake Louise is situated in a stunning location in Banff National Park. I tend to agree that it will be tough to do this on a weekend, even a long one due to no late flights on the return, unless you do a red-eye via YYZ and the fact that Lake Louise is probably about 2 hours from the Calgary airport. Not sure when you are thinking of coming but this hotel will enter its peak season very soon with rates around the $500CAD per night range. Come July and August the area will also be VERY busy. If you want to see Lake Louise I would suggest coming in late September or early October (when rates go down). The time between the end of the summer season and before skiing can offer a quieter and MUCH cheaper experience. I have a trip report posted on tripadvisor.com from a stay in February. Be warned that the Fairmont Rooms are TINY, ie. 165 square feet!!

I know nothing about Sonoma, other than it too is a bit of a drive from an airport.