I along with my wife are arriving Zurich Airport on 21 Sep 2018 and stayin at Dubendorf. Same dat we intend to do sightseeing to Bahnhofstrasse, old town and back to Dubendorf at night. Next day(22 Sep) we are travelling to Zurich Hbf in the morning and returning to Dubendorf at night. On 23 Sep we are travelling to Zurich airport to catch flight to Venice. How many zones are we travelling in these 48 Hours? Is there any travel card for this itinery? How much would it cost?