I haven't spent much time on Hwy 213 - but that looks to be your most direct route. Around Oregon City and hang a right at Marquam. There are a number of great roads heading south from ~Canby as well (Barlow, Meridian). I'd recommend the Canby Ferry long before 99E (if 213 doesn't look very bike-friendly).
"The older you do get, the more rules they're gonna try to get you to follow. You just gotta keep livin', man, L-I-V-I-N." - Wooderson
'14 carbon Synapse - '12 CAAD 10 5 - '99 Gary Fisher Big Sur