However, just one question, if you had to remove stops in order to make it a one way car rental and therefore doable in the 14-16 days, would you remove the Portland, and up the coast area time, OR yellowstone?
We all face these type of decisions when planning a trip but the good news is there are no bad choices just great options. You would have time to do the full trip, it's at what pace you are prepared to travel at. Are the ferry rides a 'must do' for you ? Seattle >Yellowstone >Portland >Olympic >Seattle would make a great loop with lots to see in between, but ultimately it's your decision to make.