We (parents + 10 year old boy) will be visiting in Seattle this July. We're booked for a cruise to Alaska and when it ends back in Seattle, we want stay and spend a day or two in Seattle and then drive our minivan all the way to Yellowstone N.P. via scenic routes. We have allocated 4 full days to the trip from Seattle to Yellowstone and would like to get the most out of these days. We've checked the maps and read a bit but can't decide which routes will be best. Please suggest a sensible scenic route and best places to stop in between.