John,
USPS Priority Mail isn't the cheapest way to send them, but should get them where they are going a little faster. Most folk are willing to pay for the option, or reciprocate in kind for a trade - at least I am, LOL.
The Post Office provides free Priority Boxes, but they are a little large. I save Saran, wax paper, and aluminium foil boxes (with or without the tubes) and use those for shipping cuttings.
It should be OK to ship to the NE now, but a heads up e-mail or post when you ship will help.