I hope you're going back before June 21st. From June 12 to 22 (some sources indicate termination on the 21st), there will be a major milair exercise along the N.C coast.
http://www.faa.gov/NTAP/NTAP04MAY13/mil04005.htm
Simultaneous activities will be occuring at other U.S. and foreign locations, in conjunction with this exercise.
http://www.jfcom.mil/about/exercises/cjtfex04.htm
I do not normally monitor military communications, but here's a couple of sources to gather additional information:
-- George Fetters' www/milaircomms.com has some frequency information, plus a link to subscribe to a good milair group on Yahoogroups.
-- The First Flight celebration got some good frequency coverage on the obx_scanning list on Yahoogroups, and this is also a good - but small - group for Outer Banks information, in general. Two diehard milair hobbyists on the list ... Jack Painter (the Oceana Radio website) and Rich Rowland. There is also a member who is involved in tech work on the Navy's remote sites on the Outer Banks.
-- The Charleston-Scan list on Yahoogroups has a few diehard milair listeners. Look for Mark Cleary, and list owner Paul Jones.
-- There have already been some posts on the ScanSavannah list on Yahoogroups related to the cjtfex04 exercise, including a post about expected related communications in the coastal S.C. / Ga. areas. List owner Roland "Mac" McCormick has an ear to the scanner, and an eye to the sky 24/7, with regards to milair comms on HF/VHF/UHF.
Since the exercise starts before your visit to the Outer Banks, the four Yahoogroups mentioned above should give you an indication of frequencies being heard in use, as well as callsigns and usage.
You might want to subscribe to Jack Painter's "iscanmarine" Yahoogroup, which is dedicated to search-and-rescue marine and air comms. In the past, Jack has run live audio on the list site. He might have plans to do something along that line during the exercise.
BTW - Depending on where you'll be staying on the Outer Banks, a trip to the Dare County Bombing Range might be of interest. There is a public viewing area. I believe the Public Affairs officer at Seymour-Johnson AFB handles information about the range, and you can call the morning of a potential visit to find out if the range will be in use that day.
Jeff Multer
Fort Mill, S.C.