Thanks for all the help! It seems there are two possible trips that will work out best
1) An "inland" trip coming from somewhere near Glacier NP, and ending in Vancouver, possibly going through Jasper
2) A "coastal" route around the San Juan Islands, Vancouver Island, ect
I am leaning towards the inland trip as I feel that it will have less traffic, and possibly better weather (less rain). Less traffic is a big deal to me when I'm touring, and less RV's/Vacationers sounds like a big positive. Does my thinking seem reasonable here?