Hi! A good place for you to look would be the Raleigh Visitor's Bureau website at
Raleigh's Official Tourism Site -- Travel info for your Raleigh excursion. They have lots of info on a bunch of Raleigh historic sites (not just plantations), as well as other things.
One of the things you might enjoy would be Oak View County Park. It is listed as a farmstead, but kind of has the plantation feel to it. You can visit the farm house and there is also a cotton museum. Here's a picture of the outside of it:
100_3495Historic Oak View on Flickr - Photo Sharing! (http://www.flickr.com/photos/fallingstar/812642397/in/set-72157600827209927/ - broken link)
Raleigh really has a lot of historic places other than plantations that showcase the Southern lifestyle, such as Mordecai Historic Park, Haywood Hall, and the Joel Lane Museum House. Hope you enjoy!