We're planning a trip to Canadian Rockies for our next vacation for ~ 12 days. We'd like to hit the National Parks and mostly hike (we're not really skiers). What would be the best time of year for such a trip. We probably won't camp but will stay in lodges. I would like to go when it won't be too crowded with tourist, but when there won't be any issue with road closures due to snow. Any advice would be appreciated. Thanks.