Camping options are somewhat limited in Gorges State Park. Backcountry camping is allowed along many of the trails, and a large campground is under construction as of fall 2017, but currently the closest thing to frontcountry camping are the Raymond Fisher Campsites. This is a small, primitive campground tucked away in a quiet valley. Getting to it requires a 1.5-mile hike from the Grassy Ridge Trailhead, which is the same starting point as Rainbow Falls Trail. If you don't mind a bit of work, hiking to Raymond Fisher is the perfect way to spend the night in the woods, and it makes a great base camp for exploring the waterfall trails nearby.
A well-marked fork leads to Raymond Fisher. You must carry all your own gear to get here, so pack light, but bring enough to stay comfortable. Amenities are limited to a vault toilet, and each campsite has a picnic table, fire ring with cooking grate, and lantern post. There is no drinking water. You must purify your own from small streams or the pond beside the campground. This pond is an old reservoir for a homestead that used to be here. It was once stocked with catfish, and they've persisted, but they don't grow very big. You can fish for them with a valid North Carolina state license, but fishing is catch and release only. Swimming is prohibited.
Sites are available by reservation only, whether online or at the park visitor center. You may also be able to self register and pay at the trailhead if sites are available, but planning in advance is recommended. Pets are allowed, but they should be kept on a leash at all times. If you'll be making a fire, be sure to use only dead and downed wood rather than cutting any standing vegetation.