Small plasic pipe (like central vacume pipe) cut it too length, tape up the ends. Cheapest way may be on the bus.
What he said, exactly.
You can ship stuff on Greyhound that is some weird sizes pretty reasonably. I've had friends ship some expensive RC stuff this way that is too big to reasonably send via Fed-EX, UPS, or USPS. You have to go to a terminal, or possibly arrange pickup at one of their schedule fuel/piss/driver swap stops, but from what I understand its not rocket science.
Battens shouldn't be that bad, even though they are long. I've used Fed-Ex for sails within the states a few times and not had any issues. Lots of stretch wrap to make it a bit more solid of a package.