Charles had conceived the idea for an intensive summer training camp for aspiring orchestral musicians in the 1950s when he was the conductor of the Wichita Falls Symphony Orchestra and chose Estes Park after vacationing there with his wife.

This was a requirement for all the musicians, regardless of their ability to pay for their room and board, and one which Charles described at the time as "part of the philosophical training of the Blue Jeans program."

The orchestra performed their concerts in blue jeans, and Charles conducted in a denim white tie and tails especially made for him by Levi-Strauss.

The orchestra hired its first business manager and placed an emphasis on stipends and scholarships which allowed the students twelve-hour days devoted to practising, rehearsing and performing in concerts.

[1] In 1985, the orchestra performed at the Kennedy Center in a concert celebrating the 20th anniversary of the National Endowment for the Arts in a varied program of 20th-century music that included Billy Taylor playing his own Jazz Suite for Piano and Orchestra, Joel Hoffman's serial piece Between Ten, and Aaron Copland's A Lincoln Portrait.

The increasingly peripatetic performances at Evergreen led to the Denver Post calling them "the guerilla orchestra" because they never knew where they would be playing next.

[1] The orchestra, conducted by Gilbert Levine, performed in Denver to mark Pope John Paul II's visit for World Youth Day in 1993.