Re: British Columbia

Coming this far, you should try to visit the Icefields Highway between Jasper and Banff/Lake Louise area.
In Victoria, Vancouver Island, visit Butchard Gardens, beautiful gardens and should be bloom in your time frame.
Capilano Suspension Bridge is a good sight along with short walk through the large timber.
Hell's Gate is a sight. It will not have large amounts of water during your time frame. It is a wonder during high run offs.
Stanley Park in Vancouver.