Having done the same thing, (and probably will do it again, this year) I'd go with the suggestion of doing both. Originally I had planned on spending 2 months in Tahoe, last year. However, weather wasn't cooperating, so I drove from the East Coast to Colorado. I spent 3 weeks in Colorado, then moved-on to Utah, then on to Tahoe. That was the best move I could have never imagined! Moving from place to place was great! And, honestly, my time in Tahoe was the snowiest part of their winter....I enjoyed it, but was ready to move-on.
If you want to settle-in and become part of the cultural fabric of a ski town, then you'll probably want to do your full time in one spot....which I think is foolish. But, since you have friends in either place, you MUST just go and hit all the places. Get the full-on US experience.
Colorado is much different than Utah! Many Utah resorts get more snow than the Colorado resorts. The elevation is much greater (2-3 thousand feet more) in Colorado than in Utah, therefore it is much much colder.
Along a Corridor from Denver to PC (which is a 9 hour drive) you could essentially visit....
Keystone (I don't know why you would want to)
a short off-shoot to Aspen & Snowmass
Strongly suggest hiking Hanging Lake in Colorado if it is accessible
Then off to Utah where I Strongly suggest wandering down to Moab, Utah for a day to hike Arches National Park....a must-do!
From there you could drive to PC and ride
And if you are feeling real feisty and have the funds to do it, Jackson Hole is about 4-5 hours from Park City.
Spread yourself out. If you are able to capitalize on this, you'll have little need for Whistler.
If you ski, Check-out "The Mountain Collective."
Also, I strongly suggest the Epic Pass! Breck, Vail, Keystone, Beaver Creek, and Arapahoe Basin.....and if you find yourself in California.....Heavenly, Northstar and Kirkwood. I know people hate Vail, but it has its shit together!
Traveling the States and Taking Pictures