You could also plan a trip using the SBB website, www.sbb.ch
which you can put into english. Then you put in your starting point, destination, date and approximate time and it will give you a choice of journeys. It will tell you which platform trains go from, and you can expand it to show all intermediate stops so that you can check you are on the right train! It also has all the buses on there too. Then you will know in advance what time trains leave (both there and back) and where to catch them from.
If you do move here you can buy a year travel pass, valid through the whole canton of Zug, including trains, buses and boats(I think). Its called a Zugerpass. Then you don't even have to ask for tickets if you are staying within Zug canton. If you go further you can buy extension tickets to cover the rest of the journey. Your 4 year old will travel free with you. Your 6 year old would need a ticket. (Here 6 is the magic birthday where you start paying for transport, entrance to attractions etc.).
Another thing, again if you move here (or even if you plan doing a lot of train travel over the summer) is you can buy a "Juniorcard" for your 6 year old which means all his/her train travel is free for a whole year throuhgout the whole of Switzerland if travelling with a parent. It costs 30chf for the year. We bought one for our daughter when she went on a trip up to the Jungfraujoch and it was cheaper to buy that than a normal one day return.
One good thing about travelling on public transport here is that everything is usually pretty much on time. Good Luck!