I would suggest day trip to Whistler as well, you are right, it is a tourist destination all year around, but the Sea-to-Sky highway trip is worth it. I suggest to get a good radar detector for this, as you will not be able to follow the legal speed limit (I noted your good intention to
). At Whistler you can either just look around the town, or take a gondola to the peak and have a short hike. Again, it can be done in one day.
Hard to suggest anything in the city, if you dislike tourist places. Stanley Park is given, you can even drive through it, if desired.
You can visit
BMW Car Club of BC to ask local BMW drivers for suggestions.
Another option is to take ferry and swing to Vancouver Island / Victoria.
On the way across the Province, you can make a stop in Penticton in the Okanagan Valley, if you are into wine, visit some local vineries for a tour.
From there, aim for Banff in Alberta and drive to Calgary from there.