Raleigh, NC

I believe the fairgrounds would be the closest but they are limited to 14 days. NC State Fairgrounds

The folks running the fairgrounds campground will likely work with you on the fourteen day limit if you're involved with something associated with the University. Sure wouldn't hurt to give them a call to discuss it.

I think the schools transportation system, Wolfline, provides service to Carter Finley which isn't very far from the campground.
http://www2.acs.ncsu.edu/trans/wolfline/schedules.html

Maybe you'll have time to visit the Outer Banks (3-4 hours from Raleigh) for a day or two after the second week to keep things legit.

NCSU is a great school in a great town. Go Pack!!!

If you can't stay the full month, maybe spend a little time at Jordan Lake. Several campgrounds there and still not too far from NCSU. We really don't have too much else.

We stayed at Jordan Lake. Nice campground but a disadvantage is they close the gates at night with no going in or out.

Four Oaks resort and RVacation are within 40 miles of Raleigh if all else fails. RVacation is right off of I-95 near the Kenly area. We have stayed at both of them.

Thanks to all for the help we are going to use the fairgrounds

Normally the fair grounds will work with you on the 2 week rule. Last year there were several rigs there for a couple of months while transient techs worked on scheduled nuke plant maintenance nearby. That was in late winter/early spring though when there was not a lot going on.