"Farmer said he'd be my Virgil here"
The Barque of Dante
Public DomainThe Barque of Dante - Credit: Eugène Delacroix

Virgil was a Roman poet who wrote the Eclogues, the Georgics, and the Aeneid.

In Dante's Divine Comedy, Virgil guides Dante through Heaven, Purgatory and Hell.  Most famously, he shows him the nine circles of suffering, to which Farmer may be comparing Haiti here.