Consider any of the Backcountry Discovery Routes. These have been developed with adventure motorcycling in mind but many of them would be suitable for bikepacking.
www.backcountrydiscoveryroutes.com then click on ROUTES. They do not use singletrack. You would need to determine your resupply points. They provide routes but I don't think they provide any printed info on camping or food.
In their ABOUT section, note that for each route that have a full-length documentary DVD, paper maps and GPS tracks.
You can also read ride reports on all the routes by searching the ADVRIDER forum.
www.advrider.com/index.php Search in Ride Reports or Regional Forums for the routes by name such as ORBDR for the Oregon route.
We did about half of the routes in Oregon a couple years on our dual sport motorcycles. It was great. You could create a loop.