Cripple Creek is a folk song in the Appalachian tradition, using harmony, fiddle, and piano (in the style of a strumming guitar or banjo). The conductor can treat the choral parts as the basis for improvisation as well, adding bent notes, glissandi, etc. as appropriate to the ensemble. The clapping parts can be ornamented, especially the sections that go back and forth between the right and left sides of the choir. Treat it as a playful competition, and allow it to get more complex as it suits the choir.