Final answer:
Chris McCandless appears to have been the least mentally prepared for his chosen adventure compared to Everett Reuss.
Step-by-step explanation:
Both Everett Reuss and Chris McCandless embarked on challenging adventures, but Chris McCandless appears to have been the least mentally prepared for his chosen adventure. While Everett Reuss had prior experience and training as an explorer and artist, McCandless was undeniably unprepared for the harsh Alaskan wilderness. McCandless lacked the necessary survival skills, underestimated the challenges he would face, and did not sufficiently plan or prepare for his trip.