Thanks again to everyone for all the info!

I've been thinking about where to stay and this is what I have come up with. I would appreciate any feedback/advice that anyone has on this! Thanks again!

Day 1: Fly into Seattle
Day 2: Seattle
Day 3: Drive from Seattle to Vancouver
Day 4: Drive from Vancouver to Whistler (spending the day in Whistler and and the night in Vancouver)
Day 5: Drive from Vancouver to Victoria
Day 6: Drive from Victoria to Westport, WA
Day 7: Drive from Westport to Astoria, OR
Day 8: Drive from Astoria to Portland
Day 9: Spend day in Portland and drive from Portland (stopping along the way at Mt St Helens, etc)
Day 10: Fly back to Dallas