The Pynchonian historian
what intoxicants were available?
what subversive groups plotted against what power elites?
what superstitions lingered at the fringes?
what new scientific theories mathematical metaphors metaphysical speculations were about to stir up controversy?
which old ones were fading from fashion?
what was the general state of language and literature?
then take the standard comic ethnic stereotypes
and contrast them against anachronistic human hipsters (who enter poetic fugue states at the drop of a hat)
and glimpses of real love
find fitting names for streets and bars
camouflage your painstaking researches by alluding to the worst obscurities in the most offhand way