Tusayan

This is not a developed site, which means it's perfect :) Bring your own water and find your own campsite within the allowed area (get a map of the area from one of the self-serve or ranger stations from the US Forest Service). This is a great area to get away from the ever-present crowds in many of the campgrounds around the Grand Canyon. It can be a little hard to find a site (since there are none specifically designated) so plan to drive around a little bit. You can walk as far from your car as you want and pretend you just went backpacking all day, or camp right in the ditch by the road. Lots of wildlife (so many elk!), close to Grand Canyon, mostly wooded, rocky ground (but fine for getting stakes in). I had cell service here in 2012 so you can be connected if you choose. 

Backcountry camping in Kaibab National Forest near Grand Canyon 

My BF and I drove to the Grand Canyon from N California with no reservations and found this gem of a dispersed camping area. Located only a couple of miles from the entrance station and right outside of Tusayan, AZ, the Kaibab Natl Forest has plenty of space and it's free! While there is no pit toilets or running water, the road we camped off of (USFS RD 302) had established drive-in sites with fire rings!  We were in a tent so I'm not sure RVs would fit. We we're only staying a night so this quiet free spot was exactly what we were looking for! There were a few other campers around, but it was really quiet compared to the cramped campgrounds we saw in the park.  If you're looking for free Grand Canyon camping with no frills definitely check this option out!

Dispersed Camping in Kaibab National Forest

If you are looking to car camp/backpack and the campgrounds near Grand Canyon Village (south of south rim entrance) are full, or you simply want to camp on the cheap and without any neighbors, consider boondocking in the Kaibab National Forest. All of the area has fire roads (which you can look up/explore until you find the right spot that suits you) and you can basically just set up anywhere. The roads are dirt/gravel so expect some uneven rides, but all the ones that we drove on were extremely manageable. Fire service road 306 is where we spent the majority of nights, and even though it was close proximity to the Grand Canyon airport, it was extremely quiet and peaceful with elk walking past and coyotes howling in the distance. Obviously, no amenities exist, will need to bring plenty of water and food for the duration of the stay. The Fire service roads can be easily accessed by turning immediately off of route 180. The small herd of elk that passed by were very indifferent to us, but it should go without saying do not approach any wildlife if encountered while camping in the Kaibab forest. 