Getting delayed on your JFK-RDU leg and having your unit locked up after closing time at the UPS/FedEx location will be even more annoying than just keeping it to 10% over for that measly two hours. For that matter, even if the schedule works, adding that stop will eat up nearly as much time as you can gain back safely on a two-hour drive in eastern or central NC in an unfamiliar rental car. I've spent a significant amount of time driving all over NC. It is not Oklahoma; this is not flat-and-straight country where you can see everything coming at you miles away. It's also deer mating season out here. Hitting one of those guys at 90 will ruin both of your days.

You are talking about a significant amount of trouble for very little gain here. If you absolutely must have your radar detector in NC, ship it to somewhere near your destination.