The worst part at the moment is Kenton to downtown Vancouver, IMO. Northbound on Columbia St. in Vancouver is a pretty mellow ride.
I'd probably cheat and bus it to North Van if I were you also. If you ride from 99th St. Transit center all the way in to Oly it'll be over a hundred miles. I ride I-5 up to Tumwater from my place on 63rd in Hazel Dell and it's right around a hundred miles.
Day and month Trimet passes work on C-Tran, otherwise you'll have to pony up $1.50 to catch the 4 bus across the river, then another $1.50 to catch a ride up north.