I'm an RN who graduated in May '05. My orientation was 40 hours/week from July-October '05 and since I've been off orientation I work 24 hours/week. I can pick up extra shifts if I choose, but it was important to me to only be REQUIRED to work 24 hours/week because I'll be starting nursing graduate school in a few months. So it is possible. But I also agree that it's a good idea to try to be in orientation full time since more time to practice your skills is best.

-Christine