I will say, listening to Ghost Soldiers really opened my eyes to what is possible. You got guys living on bugs and monkey stew for months, suffering from malaria, dysentary, trench foot, and who knows what else, get captured, march for a week with maybe a cup of water a day each in the tropical sun, and little or no food, and getting cut down if they break rank or fall behind. Then they wind up in POW camp, with no medicine, and little food or water, and hang on for 3 years. That book permanently reset my views on what is possible.
An equivalent might be doing RAAM, but getting one water bottle every other day, 1 Powerbar a day, breaking out once into a malarial fever for a day while your friends carry you on your bike, and stopping and defecating every thirty miles for most of the trip. Unbelievable.
[I did notice an "a" transposed with what should presumably be an "o" in the title]