可以，但必须注意如下事项

Both near (outside) the south (AZ64) and north entrance (AZ 67), it belong to Kaibab National Forest, and you can camp or sleep in car in the Kaibab National Forest. Please make sure you stay in the Kaibab National Forest, not the design camp site. There is design camp site outside the park too, but need fee. And make sure you are not in the "day use area". Ticket is $250/per person. Good luck.