I will stick my neck out here and say that older teens, with some experience, are capable of going on an overnight by themselves. You need to loosen the noose as they grow up! By the time they do their own route-finding, cook all meals, set up camp etc, they will be quite busy. As they go off to college they undoubtedly will go out with buddies and you will have absolutely no influence or say. As high school juniors or seniors, you can ease them into this by helping with the planning phase, be sure they are properly equipped and trained, and then just let them go. If there is cell phone coverage they can call you once they get to their destination. At some point you need to trust them.