You'd have to be nuts to ride the sea to sky on a bike… people on cellphones paying no attention to the road combined with many sections that have no shoulder. gah!
It's sort of lower mainland, if you want a low traffic ride and don't mind going through the border, drive your car to white rock, park it at the shopping mall at 16th ave and 152nd, and ride to Bellingham. It's about 42km from white rock to bham, flat, and the locals in Blaine can direct you to the low traffic roads. Almost everyone in a car takes the I-5 freeway to go south. On some rides I've been passed by a total of four cars, on a saturday afternoon.
http://local.google.com/local?f=q[HTML_REMOVED]hl=en[HTML_REMOVED]q=blaine,+wa[HTML_REMOVED]ie=UTF8[HTML_REMOVED]ll=48.927688,-122.6548[HTML_REMOVED]spn=0.140979,0.396194[HTML_REMOVED]om=1
Take a look at that link. The peninsula on the left hand side with the Semiahmoo golf and country club has good roads and is really low traffic. Ride in a loop around there, go south through birch bay to Grandview, and then east on Grandview and turn south to Ferndale. Ask the locals for directions, they'll be really helpful. From Ferndale ride south to Marine Drive and into Bellingham on the south side of the airport. If you want a really long ride, keep going all the way down Chuckanut drive to Skagit county and turn around.
It's almost exactly 100km to go from Blaine to Sumas and back, directly east, via country roads. All of the traffic is going north-south to the Guide Meridian Lynden border crossing, there's very little West-East traffic. The Birch Bay Lynden Road from the ocean to its eastern end is a good route.
As you can see from the map here it's mostly farmland similar to Delta or Richmond:
http://local.google.com/local?f=q[HTML_REMOVED]hl=en[HTML_REMOVED]q=blaine,+wa[HTML_REMOVED]ie=UTF8[HTML_REMOVED]ll=48.938288,-122.537899[HTML_REMOVED]spn=0.070475,0.198097[HTML_REMOVED]t=h[HTML_REMOVED]om=1
"Bicycling is a healthy and manly pursuit with much to recommend it, and, unlike other foolish crazes, it has not died out."
- The Daily Telegraph (1877)