Fantastic for you to guide your parents to the Outer Banks. It will be a memorable time. One of the best memories of my life was taking my parents there for the first time back in '84 (unfortunately, it was the only time as my dad passed away the following winter). Enjoy every second, even while lined up in the heat to tee off You've gotten some great guidance here. I'll just ad one more item. Be sure to check out Duck Donuts. It's just the like the Fractured Prune in OC. I'm not a big junk food person, but I can't resist a really good donut.
the apple uglys at oragne blossom bakery in buxton will beat the pants off of any pastry anywhere! they're soooo good, but you need to go up in both width & thickness of your board if you eat more than 1 of them.
ocracoke go all the way down, take the ferry and hang out in ocracoke-it's quiet and the locals have their own dialect (for real). on the other hand, aside from the water, there's not tons to do in ocracoke, as far as kids are concerned, so if you might need some mini-golf, etc. the spots discussed above can all deliver. also, if kids' ages allow, check out all of the national parks that allow camping. there are 5 or 6 if memory serves, all with showers and bbq pits, and the best spots are right in the dunes with spots for parking right nearby-a nice way to cut a night or two of hotel bills out of the budget.