My friend and I will be traveling to Switzerland from the US. We will be going to zurich, lucerne, interlaken, lausanne, geneva. We will also be going to Milan from interlaken. My question is should we buy the swiss rail pass and if so, which one, or the eurorail pass since we will be in milan 2 days? Also what about the swiss half pass? And should i buy the pass before i get to switzerland? Thanks for any help..