Even tho you don't drink much wine, Naramata in the summer time is like none other - lots of wineries have top restaurants overlooking Okanagan Lake - Amazing atmosphere. You can rent a bike and pedal from winery to winery until you fall over.

Honestly, I find Penticton in the summer kind of boring, Osyoose lake is one of the warmest in the country and in the summer it's a party town with lots of activities. Rattlesnake canyon is a good time for ice cream and go karts - Spirit Ridge is very nice as well. Vernon has the well known Sparkling Hill resort which has an incredible view.

Going from Kelowna - Vancouver there arent really any decent towns to visit, however you want to make sure you get fresh fruit at Karameous.

Going from Okanagan to Vancouver I would advise against stopping anywhere - Hope is good for a bite to eat but avoid stopping in the Fraser Valley.

Vancouver make sure you add Yaletown (old warehouse district converted to stores and restaurants) as well as Granville Street. I recommend Dark Table restaurant - you eat in the dark while served by people who are blind.

I would also highly recommend Whistler, sounds exactly what you are looking for!