Boulder CO to Bellingham WA advice
I am planning a trip this summer, due to work I will be leaving late July. Since the bike that I have is a 2009 Rockhopper Pro and I am already fairly close to the Great Divide trail it seemed like a logical choice. I am going to take the Great Divide to the Northern Tier. I'll take that to Everett WA.
As for getting to Bellingham from Everett, I was considering HWY 104 through Whidbey Island then HWY 20 to HWY 11. Any advice here would be nice. I also am not sure on the route that I'll take to get to the great divide trail.
I lived in Bellingham in the 70's and 80's so this is old information. I rode from B'ham to Everett and on to Seattle three ways. One was down Highway 9. It was beautiful until about Sedro Woolley. Then it became unpleasant - straight, no shoulder, lots of traffic.
I tried a different route. I don't remember the details, except I rode through LaConner and the Tulalip Indian reservation. It wasn't so great.
By far my favorite route was down Whidbey Island. I'd ride south on Chuckanut Drive, head over through Bow-Edison, and go down Whidbey Island. I ride on the main highway down the island, but there are less-busy routes available. I think the Cascade Wheelmen have some routes on their website.
Once you get to Mukilteo I can't help you much. I went over to Aurora (99) and rode down to Seattle. You could probably go over to 99 and head north to Everett, but I'll bet there are nice roads to ride.