With the onset of the Great Depression, the city canceled Boone's contract, but his interest in education continued, serving with the Oakland Public School system.

In 1930 Kurt Barthel had formed The American League for Physical Culture (ALPC), America's first nudist organization.

He traveled to Germany in the early 1930s to visit Freilichtpark (Free-Light Park) near Hamburg, the world's first naturist resort, which had opened nearly three decades earlier.

In 1936 Boone opened "Sunshine Park" in the Mays Landing section of Hamilton Township, New Jersey (near Atlantic City), and established the national headquarters of the American Sunbathing Association there.

He encouraged regimens of calisthenics, abstinence (alcohol), complete nudity regardless of the weather, and vegetarianism for all members and their guests.

Nearly broke, Boone lived his last years in the home of National Nudist Council member Edith Church, where he died on Thanksgiving Day, 1968, in Whitehouse, Ohio.

Even with the genitalia airbrushed out of the photos of nudists, the United States Postal Service decided the materials were obscene and could not be distributed through the U.S. mail.