Lifelong resident of BC . . .
I would also put Whistler at the top of the list but also add Victoria as a consideration.
Whistler:
Travel - YVR to Whistler is a 2-ish hour drive and the Sea to Sky Highway section is scenic. Whistler to Penticton is a 6-ish hour drive. A couple of different options but I would suggest Highway 99. It can be slow going at times with RV and truck traffic but I find it the most scenic and it would also be a different experience than backtracking on the Sea to Sky.
Accommodation - Lots of affordable options right in the Village and you could pretty much park your car the entire time you’re there
Tourism - Endless list of stuff to see and do
Training - The IMC bike and run courses are basically right out your front door and Alta Lake is about a 10 minute drive. One thing of note is that it looks like the pool may be closed for annual maintenance the week you’d be there.
Language - Bonus, it seems that about half the population of Whistler speaks Australian
Victoria:
Your 2-3 weeks in the Rockies will be a mountain vacation and as would Whistler. If you’re wanting to mix things up, Victoria would have more of an urban oceanside sightseeing vibe.
Travel - YVR to Tsawwassen (Ferry) is a 1-ish hour drive. The ferry to Victoria (Swartz Bay) is 1:30-ish and very scenic but you definitely want to make sure you have reservations. Swartz Bay to Downtown Victoria is 45:00-ish. Heading to IMC, Victoria to Penticton total travel time (drive, ferry, drive) is probably 7-ish hours
Accommodation - I’m sure there are deals you could find but generally speaking I’m thinking probably more expensive than Whistler but nothing crazy
Tourism - Endless list of stuff to see and do but definitely more of an urban experience than Whistler
Training - Lots of swim (OW and pools), bike and run options and the Victoria 70.3 is based out of Elk Lake. Unlike Whistler and depending on where you’re staying it would require a bit of planning and a commute but nothing too difficult. As an example, Elk Lake is about half way between the ferry terminal and downtown so most accommodations are probably only 30 minutes away at most.
Vancouver:
Not on my list but only because I have no idea about the logistics of training. It’s a beautiful city with lots to see and do. If you’re interested in more of an urban vacation, I’m guessing that with a bit of research and local knowledge it’s probably easier than you would think to plan out some training routes and locations
Wildfires:
I know, a bit of a downer but I thought it was worth mentioning. The number and magnitude of our wildfires has increasingly become a very significant problem. It’s impossible to predict when, where and how bad but air quality issues from smoke will be but it appears to be the new norm throughout the summer and throughout the province. If race week training is really important to you, wherever you decide to spend your time you might want to line up some indoor training options just in case and this is why I mentioned that the Whistler pool may be closed when you’d be there.
Good luck with your plans and race.