I have been to Cape Hatteras many times but never with my bike. That said, certainly Rt 12 is a no brainer - stay away. BUT, people do LIVE there, and ride bikes. Just need to stay off of 12, maybe you need to go inland a bit, but I think you could find some good rides there. Yes, it will be windy. And sand blowing is not fun. (Be sure to clean bike well after your trip).

Vermont Bike Tours
http://www.vbt.com/
runs tours from New Bern down to Okrakcoke and back - so maybe you can glean some insight from the itinerary for that trip?
http://www.vbt.com/North-America/Uni...Itinerary.aspx

I took a VBT tour last fall - it was fabulous. I can't wait to do another one.

Also check out bike shops and clubs for ideas on riding down there. I would definitely take the bike. Better to have it and not need it than be moping around wishing you had brought it with you.

If all else fails, rent a bike, or go to some big store and buy a cheap one to use for the week. At the end of the trip, donate it to some thrift shop or church or someplace, and take the tax deduction.