Leave them on the vine, the frost won't bother them.

NC here also, but I cut mine this week. Frost may not bother them, but freezing may cause rot after thaw.

Last year the ones we missed harvesting (they were WAY up in the trees) came out much better than the ones we harvested and brought inside. If they are not ripe enough, they will rot no matter what you do.
JMO,
Tom

We leave ours on the vine until the STEMS are brown and dry. The gourds will be losing some of their water weight, and will still be green/turning brown.
Good luck!

Jan