Dave Hunt got three out of four of the answers: Town Crier, IFPD and Chamber of Commerce (now defunct or the community would still own Town Hall). Rustic Theatre was another of his guesses but it opened in 1948.
The fourth 1946 establishment that just celebrated its 70th anniversary is Idyllwild Arts, formerly Idyllwild School of Music and the Arts. That was a lively year for Idyllwild.