We are a family of five, boy=15, girls = 13,10; we live in the south west of Western Australia. Our plan is to spend two weeks (6-20 December) travelling from Seattle to San Francisco and my plan is to return along the Pacific Coast Highway. We would like to see the mountains, forests, visit Mt St, Helens - we know we don't have enough time to see the Grand Canyon but would like to see canyons too ( I have read that there are great geological features in Oregon.) We want to visit Yosemite and spend about three days in San Francisco. My concern is getting the timing right- I have read that Seattle is a great city to visit too- if we allocate 3 days each for San Francisco and Seattle do we have enough time to drive and see some sights in WA, OR and CA?