You need experience before you can start traveling. A year should be fine, you may not be able to get the highest paying gig with that experience, but you can get your foot in the door.
From my experience, they do not want you to do OT. Paying time and a half for a traveler is obviously way more than a staff nurse. If they're desperate, sure, but I wouldn't come in expecting it.
Same duties you have as a staff nurse. Possibly less because you're not usually having to be charge (this varies honestly), not in charge of any teams, nor do you have to do all those nonsensical trainings and what not. I work as an operating room nurse and I scrub and circulate, that's my specialty.