I took a look at the frontcountry camping page just now, and it isn't looking good:
It doesn't say, but since there's no link to make a reservation, it would seem that Cataloochee is unavailable. I took a look at a couple of the other sites that have some spots (Cosby, Elkmont), and it looks like only Friday is available.
I second Hugh's comments on the road into Cataloochee...I take my time going in there, and I'm driving a car. There's a lot of blind curves until you reach pavement inside the park. It's tough to find spots on a holiday weekend - I priced hotel rooms in Maggie Valley, and they're either booked, or the rooms that are available are scalper's prices...big time price gouging - a room that would normally go for about $70 going for $126.