Planning to ride Portland to Boise self contained but not camping so need lodging. Thinking of staying nearer I-84 (but hopefully not too much on I-84). Route advice?
Shouldn't be a problem. Just take the nice downwind ride along the north side of the Columbia River, cross over to Umatilla on the bridge (Ignore the "no pedestrians or bicycles" sign) and head southeast alongside I84. Where there is no parallel or frontage road or "old highway" ride the shoulder. I don't see any really long stretches without a town.
Actually, there is a bicycle/pedestrian crossing facility over the river. It is accessed on the Washington side from Christie Rd. and ends at 3rd St. in Umatilla. Also, you'll be following I-82 south before you meet I-84.