I am planning a 6-wk. driving trip across the northern U.S., B.C., and Alberta. I have a choice of the last 2 wks. of May and all of June or the last 2 wks. of July and all of August. I plan to go to Vancouver Island for a week and Banff for a week. I'm torn between May, when the gardens may be at their peak, or July, when the weather will be warmer and road conditions better. I welcome input on time, as well as "must-see" places.