Purple Mountain's most recent endeavors have been in the musical theater space. After acquiring the rights to the late, celebrated, singer-songwriter Dan Fogelberg's catalog of music in 2012, Atkinson, with partner Karen Harris under their K-Squared Entertainment banner, penned the book for Part of the Plan, an original, Broadway-aimed musical featuring 19 Fogelberg songs including Part of the Plan, Leader of the Band, Same Old Long Syne, and Longer. Part of the Plan opened the Tennessee Performing Arts Center's 2018-19 Broadway season to standing ovations, rave reviews, and 15 regional Broadway World Awards, including Best New Work and Best New Musical. The show is continuing its development at Signature Theater, in D.C., under the direction of Marc Bruni (Beautiful: The Carol King Musical, Trevor). In February 2019, Atkinson produced a NYC staged reading of A Very Brady Musical, based on TV's iconic show The Brady Bunch. Soon after, Purple Mountain formed a joint venture with Broadway & Beyond Theatricals to produce the first commercial production of the show. The team mounted a virtual presentation of A Very Brady Musical with Maine's Ogunquit Playhouse, in October 2020, and plans to launch a national tour when live theater opens up in the fall of 2021.