“Steinbeck loved the writing of Cervantes, especially Don Quixote,
so much that near the end of his life he was reading the text in the
original old Spanish. When his friend and editor Pascal Covici gave him
a new edition as a gift, John responded to his wife Elaine Scott Steinbeck,
‘This book is not an attack on knight errantry but a celebration
of the human spirit.’ …

John Steinbeck saw Don Quixote as
a symbol of himself, and the novel’s morally arid time as
a mirror of mid-twentieth-century America. Thus, Steinbeck traveled
to Spain and La Mancha in 1954 out of a special affinity for the place,
and began his journey to rediscover the soul of America in a camper
he affectionately christened Rocinante. The fruits of his journey –
Operation Windmill as he called it – eventually found expression in
Travels with Charley. To the very end, the romantic ideals expressed
in the work of Miguel de Cervantes stoked the moral and
artistic imagination of John Steinbeck.” 

– Stephen K. George, 

A John Steinbeck Encyclopedia, p. 55