I have been East from Vancouver / Portland a couple of times taking several different routes (I get bored easily). Along the 84 in Oregon or on 14 on the Washington side (slower and better suited to old trucks), then up 97 to Wenatchee and up over to 90 and head east. You could also do this same thing going North on I-5 and either cross on HWY12 over White pass or go north to HWY18 to I90 and cross the Snoqualmie pass. 6 of 1 or half dozen of the other, the Southern route has easier passes. It takes a little longer to go the northern route for those down here, but we could meet on I90 east of the mountains somewhere and camp the first night.
I vote for something just the other side of the mountains. Then make Idaho on the second day and then Montana the third day. Last time I drove to Montana, left at 6:00 in the morning and pulled into St. Regis at 9:00 at night . . . average speed was a little faster clip than 45mph though . . .
