If you're feeling like Don DeLillo's Nicholas Branch and would like to lose yourself in the vast compendium that DeLillo, in Libra, called "the Joycean Book of America," the entire 26 volumes of the Warren Commission hearings and exhibits on the assassination of President John F. Kennedy can be found online here. But beware: these volumes are a paranoid's paradise.
Voices and Visions, the very good 1980's PBS documentary series on American poetry, can be viewed online here. Click on the poet's name and then the 'VoD' link on the next page to watch the entire episode.
That unfortunate 16th-century traveler Cabeza de Vaca might, at a stretch, be understood as the true and unacknowledged father of America's 'Southern literature' (which, as Garcia Marquez has admirably observed, is really 'northern' literature, the literature of the northern Caribbean basin). The Journey of Alvar Nunez Cabeza de Vaca, one of the earliest extant accounts of travel in the area now known as the American South can be read online here.
Another of American literature's disavowed founding texts, The New English Canaan, by that long-notorious anti-Puritan Thomas Morton of Merrymount--he of the Hawthorney May-pole and many merry mountings--can be read online here.
Arthur Golding's classic 16th-century English translation of Ovid's Metamorphoses, the translation Shakespeare would've known, can be read online here. I have long contended that Titus Andronicus can be best understood as a Bloomian revision of Ovid's great tale of Tereus, Procne and Philomela.
Herman Melville's letters to Nathaniel Hawthorne can be read online here.
Finally, here's a fascinating video of British SF/Fantasy writer China Mieville in leftist public intellectual mode. He's discussing the nexus of Halloween and Marxist theory, and the whole thing is more interesting than that dread word 'theory' makes it sound: