Also check out
www.adventurecycling.org. 3.5 months starting that early might be a challenge to get across the Rockies (if it snows a lot this winter, the passes will be closed or cramped until later in the year). Adventure Cycing has a pretty good route system. You could ride north to Lewis and Clark, TransAm, or Northern Tier, and head east, giving the snow a few more weeks to melt.
If you started from LA, you might also go south to San Diego, go east on the Southern Tier, north on the Grand Canyon Connector to Western Express, then catch the TransAm east of Pueblo, possibly connecting with UGRR or Great Rivers north to Northern Tier.
Have fun planning!