Depending on your start and finish point, you could check the ACA TransAm, Lewis & Clark, and Northern Tier routes and maps.

http://www.adventurecycling.org/routes/transamerica.cfm

http://www.adventurecycling.org/rout...isandclark.cfm

http://www.adventurecycling.org/routes/northerntier.cfm

These might help.

Also for many many pointers (through others' journals) try looking at Crazyguyonabike.com