Use solar string lights for a no-impact light source. The solar collector panel has to be in the sun all day but the lights can be hung anywhere, even inside a lean-to, tent or camper. You can attach the system to a photo-sensitive on-off switch that will turn on the lights at dusk and switch them off at dawn. Be kind to your neighbors, though. If you are in a crowded campsite, manually turn off the lights when you turn in so nearby campers can get some sleep, too.
Save energy with LED bulb string lights. They use about 90 percent less energy than incandescent bulbs and have an average life of 10 years or 100,000 hours. LED light is very bright so it makes it easy to find your RV or tent in the dark. You could run a string inside a tent to light it at night. LED bulbs put out so little heat that they won't overheat the tent. For an outdoor "lamp" bright enough to cook or read by, coil up a string of bluish-white LED bulbs to concentrate the light.
An all-weather light source for campgrounds is rope lighting--strings of bulbs encased in clear rubber tubing that can be draped over a convenient tree limb, fastened around the frame of a tent or used to mark the trail to the pit toilet. If you get the LED-bulb version you won't have to worry about them getting too hot near anything flammable--or damaging plants--because LED bulbs emit almost no heat. Or get ropes of solar bulbs and charge them all day in the sun while you are fishing, hiking or kayaking. When the camping trip is over they wipe down and coil up neatly and quickly to stow with your gear.
Style your camping trip with light strings to match your activities. You can find trout and bass string lights, strings of miniature camp lanterns, foxes, Airstream trailers, ducks, fishing bobbers, dragonflies or just about anything that will mark the campsite as yours.
