2. Patriarchate of Antioch (Lebanon, Syria and Antioch itself, the oldest Christians and the oldest churches)
5. St. Catherine's, Mt. Sinai
The Antiochian churches in Australia used to organise pilgrimage trips to the sites in Palestine ... quite ironic considering we're a Syrian/Lebanese-based church, who would've thought the Israelis would've allowed us in?
Nevertheless, they were quite popular and educational for the youth, but I'm not sure if they're still running them.
I'm sure other Orthodox parishes around the world would have such programs, maybe you should ask around at your local parish.
I'm particularly interested to learn about sites in Serbia. I know so little about this Orthodox country.