They certainly will admit you. The duration of the Divine Liturgy pf St. John Chrysostom is 90 minutes or so unless there is a bishop present in which case it is signifigantly lengthened; the style of the service should be evocative of a Latin mass, if you ever attended one, albeit longer. If you show up for Orthros (Matins), that service will take 45 minutes at a minimum, followed directly by the Eucharistic liturgy. The actual sermon or homily might be five minutes or less in duration. I myself and most converts are attracted by the liturgics, however, it is signifigantly longer and more intense than the Novus Ordo Missae or the servoces at an Episcopalian parish, and depending on the parish, may not be in English (due to the expatriate/ethnic segment; some parishes have two services, and still others switch between languages during the liturgy, whereas some Oriental Orthodox use screens with translations).
As far as the fish fry on Friday is concerned, I am glad it is of quality; I would avoid mentioning that to Russians or many American conwertsy like myself unless you want to hear something along the lines of "Meat on Friday? Is outrage!"
There are two Orthodox communions, the Eastern and Oriental: Eastern Orthodoxy is predominant among the Christians of Greece, Bulgaria, Romania, Serbia, Cyprus and most of the former USSR excepting the largely Lutheran and Catholic Baltic states and Western Ukraine, and Armenia; a minority of Egyptian,Albanian, Czech, Slovak and Polish Christians are EO. Then one has the Oriental Orthodox who are predominant among the Armenians, Ethiopians, Egyptian (Coptic) Christians, and the St. Thomas Christians of India; there are substantial EO and OO churches, the Antiochian and Syriac Orthodox (of which I am a member) respectively, who have a very close relationship, and who can be found in Syria and adjacent countries; there are a large number of Syriacs in Iraq and a residual population in Turkey that survived the genocides of 1915 (which affected Armenians, Syriacs, Assyrians and Pontic Greeks among other Christian groups). In the US the most Americanized group is probably the OCA, but one will find convert heavy parishes in several of the Orthodox churches, so if you have found a Greek parish and you like it, and they like you, that would be a pleasant place to go to church.