From what you are hearing, it IS do-able but you MUST be flexible and loose in your planning. Always have spare days built into a long range plan for silly things like mechanical, rain, snow, women, bars, beaches, etc! Plan for a few extra days in/due to the Rocky Mountains and if you don't burn them then lay around on a California beach! A couple high mountain passes may still be closed in Colorado but that's OK. While it may be cold with snow banks at altitude, which can be pretty awesome, the nice warm sunshine takes good care of the roadways usually as long as the snow is not coming down. Most of our towns have these little warming huts too called bars
Descend in altitude and you may very well have 75-90 degree F temps. Heavy gear to t-shirts the same day. Just be prepared. You'll have fun and see some amazing territory! For that matter you may even be able to ride up for a day of spring skiing!
First week of May during the 2011 SOHC4 Relay Rally.
Colorado - Rabbit Ears Pass near Steamboat Springs.
Vail Pass on Interstate 70 west of Denver