So you're talking the Colonial period then? I doubt you'll find much if anything, as the majority of pre-independence literature is religious, historical or philosophical in nature, with the occasional political tract or broadside ballad thrown in for good measure. Whatever fiction exists from that period is likely to be educational or devotional in nature. Even the poetry is religious, with poets like Edward Taylor following in the footsteps of England's Metaphysical poets (George Herbert, etc.) Prior to the emergence of writers like Irving and Charles Brockden Brown (whose Gothic novels with American settings were published between 1798-1801), I'm not sure there was much of a market for American-authored fiction (certainly not for novels) and even those two men wrote an enormous quantity of non-fiction to pay the bills.

You may be able to find one or two poems that reference Greece or Rome as few Western poets who've ever lived haven't mentioned them at one time or another. Not sure what you'd find would be worth the search though.

How early? James Fenimore Cooper wrote some things set in Europe, published in the 1820's and 30's. Poe's works date to the 1830's. It's probably my ignorance of the subject, but I can't even think of anyone writing fiction of any sort in the US prior to the people mentioned here and contemporaries like Hawthorne.

Have you read Irving's 'The Alhambra'? if not it's a good read.