I, too, did it in reverse continuing on to Jackson, WY from near Portland, OR.

My route followed the ACA TransAmerica maps from Eugene to near Prairie City in Eastern Oregon. Instead of continuing up into the Idaho Panhandle, I cut off on Highway 26 into Central Idaho. Here is the route I took.

You can read my journal here.

Are you going to ride this route soon? If so, be aware that eastern Oregon will be hot in August and there are some stretches where resupply is limited.

Ray