See if you can get your hand on a RoadBike Magazine, April 2007, It has a story on a fella who rode from Florida to Las Vagas, Nevada. on a Rebel 250, says it took hi 12 days. Once he got there he sold the bike and flew home. His name is Paul W. Smith and he lives in West Palm beach. He looks to be 5'8 220 lbs and the articles says he is 40 years old. I personally am planning a cross country when I retire in 18 months and it will be on a 1500 Kawasaki or if gas prices get alot worst It will be on a 250 or 400 scooter. Wag Out  

No way you need at the very least a 900, better yet an 1100. Check out the Honda 1100 shadow spirit.