I will be in Coastal NC next weekend and wondered if anyone has the inside scoop.
Plenty of good riding on the base…almost NO traffic. If you want to add miles, just head out the back gate and go to Topsail Beach…I used to head out there from my base house (officer housing near Marston Pavillion)…ride all the way to the T intersection at Topsail and back…that’s about 70 miles and can easily be 80-90 depending on the route you take on base. I don’t recommend Hwy 24 for any length…too much trash on the side…which is a pity since the shoulder is plenty wide enough for riding.
Check out the Downeast Cyclists, http://racerpig.tripod.com/. I did their Wed. & Fri. rides this week while I was on vacation in the area. They were each around 30 miles and averaged about 17 - 18 mph which made a couple of nice recovery rides for me. If you check the tri section of their web site, they have Sat & Sun rides which sound like they’d be faster training rides. They also have Mon, Wed, & Fri rides at Camp Lejune if you have access to the base. Unfortunately, I had to leave and didn’t get a chance to check out these rides.
Oh !!! A right coast Marine ??? Go west young man 
Dirt ( Hollywood Marine and a air winger to MCTSSA)