"Let's take the Mexican Bus," says your disembodied guide, "and cruise my inner barrio." It's unusual in the hospitality trade, you can't help thinking, for a group tour to begin with a collective invocation summoning the spirit of your conductor. But then we're not talking about the usual itinerary either. The tour through El Corazon de la Mission is a trip through a land with many ghostly presences, living pasts, and unscripted, undisciplined, unruly futures. It's a transgressive glide across the fronteras of the mind. How natural for it to be led by the transubstantiated life force (and recorded voice) of Mexican writer, filmmaker, performance artist, border-cruising bad boy, and longtime Mission District denizen Guillermo Gomez-Pena. Robert Avila reports for SF360.