If you have a boat you're gonna want to get a waterfront site so you don't have to wait in line every day to put your boat in and out. There are a few websites to check for info. www.lakecumberland.com
are two. Make your reservations early it can be hard to get a water site later in the year. There are tons of campgrounds off-lake too.
The lake is huge, deep, and very pretty. Check out 76 Falls. There's always a flotilla of boats tied up for partying and watching folks dive and jump off the falls. It's a great lake for fishing many species. You'll need a depth finder and a downrigger if you want to try for stripers. Make sure you have an extra gas can in your boat...it can be a loooong way back to a marina.