You can have a great trip by flying in to Calgary and then travelling west taking in Banff, Lake Louise, Rogers Pass, Revelstoke and all the way across to Vancouver and getting a flight back from there.
My recommended destinations for a summer trip would be to leave Calgary behind and head straight to Banff vi Canmore. Banff is a great place although of course pretty touristy. there are loads of great places to stay. No visit to the Rockies is complete without a visit to Lake Louise which is easily reachable on a straightforward car journey. Again pretty touristy but you can’t fail to be impressed by the amazing blue colour of the lake and the sheer scale of things.
You could then head north to Jasper or head west. We headed west and stopped off at Kicking Horse river chalets for a brief stay and white water rafting on the Kicking Horse. Great fun! Then we headed on to Revelstoke via Rogers Pass and stayed at the amazing Griffin Lake Lodge. Luxury. Amazing breakfasts. Kayaking on the lake and walks hoping to see (from a distance!) the bears. Then west on towards Vancouver with whale watching at Vancouver island (sadly cancelled due to bad weather) and a trip to Vancouver zoo before heading back home!