Agree.

Vancouver to Whistler is 2 hours drive.
Vancouver to Seattle is 3 hours drive.
Vancouver to Victoria is a 3 hour drive+ferry.

Going to any of those and back in one day is certainly possible, and I've done them, but it does turn into a long day. If you are intent on hitting all those spots, I'd suggest overnighting in each, and returning the next morning. (That will also use up some of the Vancouver time that appear to not have plans for.)

Alternatively, for Victoria, you could take a plane harbour to harbour, which would save you some time, and is a great experience. Unfortunately, that doesn't leave you well positioned in Victoria to get to Butchart Gardens (15 minutes north of the city, towards the ferry). But it does put you in the inner harbour, which has all sorts of other attractions.

I did a 9-day Vancouver-Calgary-Banff-Jasper-Vancouver circle this past summer. (I'm counting starting with our departure from Vancouver and ending with our return). We split the long Vancouver-Calgary and Jasper-Vancouver drives over two days each, overnighting in Kamloops one way, and Kelowna the other. It is about 10 hours each way without breaks--again doable, but hard, and with little opportunity to stop and admire the country you are going through. I didn't spend enough time planning, and it ended up at the limit of a "relaxing" vacation.

An overnight in Whistler give you time to see the village, do the peak-to-peak gondolla, and the kids can spend a day in mountain bike camp.

As for Vancouver:
* Museum of Anthropology
* Stanley Park
* Granville Island
* Aquarium
* Queen Elizabeth Park/Bloedel Conservatory
* Chinatown and Dr. Sun Yat-San Gardens
* Van Dusen Gardens (in case you're not gardened out)
* Gastown

Depending on where you are coming from, a whale watching trip out of Victoria or Vancouver is nice. I think the blue whales are mostly up near Tofino, so it would likely be Orca.

(Hehe. It sounds like YZF_Elite plans trips like I do, and YZF_Elite's wife reacts like mine.)