Camping on Other Planets — Clark Nielsen

What was supposed to be a fun weekend camping trip turns into a dangerous hike across another planet when three teenage boys are abducted from Earth. Their only hope of ever returning home is to escape from the laboratory that captured them and make their way across the alien deserts, oceans, and mountains. But while their journey is full of monsters all eager to attack the boys, it is their friendship and personal beliefs that are ultimately pushed to their limits.