National Park Camping

Just curious, but you say you like "rural camping" but your question is about camping at National Parks. Although there are some rural National Parks, most National Parks are fairly well developed tourist type destinations. They would still be considered rural I guess, but if you go camping in many of them (Yosemite, Yellowstone, Grand Canyon, Etc.) you'll be camping with thousands of other people. If you really like rural camping (as in remote away from the crowds) then you should look at National Forest and BLM campgrounds. And in many places on BLM or National Forest land you don't even need to be in a campground. You can just camp anywhere.