I know only famous tidbits like Alexander, buddha statues in Afghanistan . But I would like to know more about how Greek and Indian culture/philosophy influenced each other. Did Indus Valley civilization have greek influence? Are Brahmanas influenced by Plato? How did Indo-Greeks ( are these people real?) of Gandhara influence indian history.
So many unanswered questions in my head. I don't know where to start.
Nothing with Plato, any possible influence can really only be reasonably postulated for post-Alexander. Pretty much the only really iron clad evidence is the transfer of Greek astronomical knowledge through texts like the Yavanajataka and Romaka Siddhanta. These were foundational to the flowering of Sanskrit astronomical learning in the middle first millennium.
Beyond that, it is really murky. Some have suggested that the Christians of Kerala influenced the Hindu developments of bhakti that came out of south India, an I have a somewhat far out theory that Christian asceticism and monasticism is influenced by Buddhist precedent. But it is hard to say.
Grant Parker in The Making of Roman India has an excellent section on this.