I would say the important states in a General ABSOLUTELY include Florida, Ohio, Illinois, Michigan, North Carolina, Colorado, New Mexico, Nevada, Minnesota, Arizona, Alaska, and Iowa.
I omit Missouri because Missouri has not gone for a Democrat in ages. Obama lost there twice.
Now is Bernie likely to be better in a general than Hillary in states like Ohio, Florida (Which no president has ever lost and still managed to win the electoral vote), absolutely not. I think he got completely crushed in the most symbolically important states to be fair.