As per all of the above comments, but I would also add that whilst spending time in Vancouver a bike ride through Stanley Park is a must. I am no cyclist, but I have been to Vancouver twice now, and both times we have rented cycles and traveled through the park. You get parkland, trees, and the Pacific shoreline. Last time we were there (July 2019) we saw eagles, 2 river otters, and a raccoon.
Cruise ships come in to Vancouver regularly - and you can find schedules online - so walking to the harbour to view them is interesting. We have done a couple of road trips, so plenty of driving, but you can base a holiday around Vancouver no problem.
You can also get a train from Vancouver to Seattle. Take a look at the Amtrak Cascades website for details www.amtrak.com/cascades-train. It is cheap (compared to UK prices) and a gorgeous journey along the Puget Sound, and takes around 4 hours. We saw bald eagles flying, and porpoises swimming in the Sound - the from the train! Seattle and Vancouver hotels are not cheap, but I would recommend seeing both cities if you are planning to stay city-bound, rather than taking a road trip. Last time we went, our children were 10 and 12. They still rave about the holiday now (granted, it was the last one we had before coronavirus!).
Flights are expensive in the summer - it's a long way - but we managed to book ours in the Christmas sales and got flights for 4 of us for £2500 to Seattle. After a couple of nights there we took the train to Vancouver, and stayed for a couple of nights, and from there traveled by car to Banff with a few overnight stops on the way.We flew back from Calgary. (Our route: Seattle - Vancouver - Whistler - a ranch near to Clearwater - Jasper - Lake Louise - Banff - Calgary)
We saw plenty of bears and other wildlife whilst on the road. There is plenty to do throughout the Rockies: walking, rafting, zip wires, driving out early morning to spot wildlife, visiting waterfalls, Columbia Icefield (glacier)..... There is so much to see and do, but it isn't cheap, so you'd probably want to research what there is and limit yourself to one or two key activities if you can. The family rafting at Jasper was lovely, and suitable for all ages - not white water, just steady going. If I had to pick just one, that would probably be it for me :)