Zurich 3 nights as base

We are a family of 4 adults. We will be flying in and out of Zurich and we will stay in a hotel in Zurich for 3 nights (or 2 days) in the first week of August. We have never seen Switzerland and we are on a budget. On day 1 we were thinking of taking a train from Zurich to Lucerne, see Lake Lucerne (?take a boat ride too- how much does that cost)- apparently Lake Lucerne is easy to see as it just outside the train station; then take a train from Lucerne to Engleberg and then take the cable cars to Mt Titlis, and return same route back to our hotel in Zurich. Can you please give a ballpark estimate about how much will the train from Zurich to Engleberg and then the cable car tickets cost? On day 2 we were thinking of taking the Golden pass train- will that be a much different/scenic experience than the train the day before? Guess we will have to return to Lucerne to take the Golden Pass and from there should we go to Interlaken? How much might that cost- it will have to be return fare back to Lucerne and the onwards back to Zurich. Will there be time to see Zurich city itself? Zurich does not sound walkable and city tours appear expensive- any ideas? By the way, we will be flying from the US to Italy (Rome for 3 days then Florence a day then Venice by train, and then fly from Venice to Zurich, from where we will fly back to the US- our flights, hotels and inter-city trains in Italy - but not in Switzerland - will be included in our combo tickets from European Destinations.com. Will appreciate any help.