They ain't kidding about needing 4WD to get to Carova. You drive for about 10 miles on the beach to get there. Conditions vary daily from firm sand to loose, fluffy, buried-up-your-axels sand. Make sure you have a tow strap. Shovel and boards if you have room. If there's strong wind blowing on shore during high tide, the beach can get very, very narrow. Make sure you let the air out of your tires until they start to flatten out a little, like to 20psi. Makes a huge difference.
I don't think there any stores in Carova. I think it'a all houses and fire station. Kind of remote. You stock up in Corolla with all you can carry on your way out.
I'm not aware a butcher shop anywhere in the northern OBX, but there's a nice Harris Teeter grocery store just south of Corolla around the Ocean Sands area. They'll have good beef and chicken, not sure if the pork HT sells is fresh or enhanced though. There's a Food Lion in Corolla and a small "gourmet" grocery in Duck.
There'a a Walmart on Hwy 158 in Kitty Hawk. That may be the only place to get a brisket.
It's nice out there though. Have fun!