I've camped/visited Devil's Fork State Park numerous times, and each time has been amazing. There are few places in the southeast that are as beautiful as the crystal-clear waters of Lake Jocassee!
The first time I visited, we reserved a drive-up campsite, which had an on-site fresh water pump and electricity hookup (although we didn't use it). The second time, we went with one of the hike-in campsites, which are a little closer to the water. The hike-in sites are still very close to the parking lot, so they aren't too "rustic" compared to other campgrounds I've been to. The hike-in sites have access to a community fresh water pump. The drive-up sites are arranged in a loop, with a central bathroom/shower/laundry facility available 24/7. I believe there are about 4 toilet stalls, 2 sinks, and 2-3 showers. It's also nice that it is heated in winter! The laundry facility has washer and dryers which you can pay for with quarters. I don't remember there being any detergent, etc., available for use, so if you plan on using these, be sure to bring your own. We had no intention of doing laundry during our stay, but we were immensely grateful for the dryers after all of our clothing and sleeping bags were soaked in an overnight rainstorm!
The people who work at the Devil's Fork ranger station are so friendly and accommodating. We were running late on one trip, but called ahead, and they had no problem leaving the gate open for us and allowing up to check in early the next morning. Plus, they had great recommendations on what to do and see during our stay, and their gift shop sold several things (such as firewood) that could come in handy if you forget to bring your own!
We rented our kayaks from the Jocassee Outdoor Center (http://www.jocasseeoutdoorcenter.com/), which we've had terrific experiences with. Their prices were affordable, they are very friendly and knowledgable, and they delivered our kayaks to the Devil's Fork docks in advance. Be sure to ask for their map of waterfalls in the area! They are really beautiful, although I'd recommend checking the water levels first, if possible. :)
Jocassee itself is absolutely beautiful. The clear waters contrasting with the rocky and red clay shores looks like a natural wonder from another planet...not like something you'd find in South Carolina! Water sports are great here, as is fishing and swimming. Even just walking along the shores offers beautiful views and is somewhat challenging at the rockier parts. Because it is a smaller campground, the large lake never feels too crowded. Jocassee is a man-made lake, and there is actually a small town at the bottom of it. Those who are scuba-certified can scuba dive down to the town and explore old churches, school houses, and even cemeteries, which I'm sure is a unique experience (although I've never done it myself).
All in all, Lake Jocassee and Devil's Fork State Park are truly jewels of the southeast and should not be missed!