Let It Snow for Dixieland band is arranged for Clarinet, Trumpet, Tenor Sax, Trombone, Baritone Sax, optional Tuba (with Bari Sax. cues) and one Rhythm part, which includes piano, drum and bass parts.  Very delightful and fun to play.  Check out the score sample to see the instrumentation.  All parts are written out but there is an "open" solo section to allow for improvised solos.